configure fails to detect OpenSSL with gcc5

Building curl 7_47_1 on linux64, linking to Openssl 1.0.2g libs, 'configure' reports "fail" @ "checking for OpenSSL headers and library versions matching"

It appears to be non-fatal ...

which openssl
    /usr/local/ssl/bin/openssl
openssl version
    OpenSSL 1.0.2g  1 Mar 2016
pkg-config --cflags openssl
    -I/usr/local/ssl/include 
pkg-config --libs openssl
    -L/usr/local/ssl/lib64 -lssl -lcrypto 

git clone git://github.com/bagder/curl.git
cd curl
git checkout -b curl-7_47_1 curl-7_47_1

echo $LDFLAGS
    -L/usr/local/ssl/lib64 -Wl,-rpath,/usr/local/ssl/lib64 -L/usr/local/lib64 -L/usr/local/lib64 -Wl,-rpath,/usr/local/lib64
echo $LIBS
    -lssl -lcrypto -lssh2

./buildconf
./configure --with-ssl
    ...
    checking for openssl options with pkg-config... found
    configure: pkg-config: SSL_LIBS: "-lssl -lcrypto "
    configure: pkg-config: SSL_LDFLAGS: "-L/usr/local/ssl/lib64 "
    configure: pkg-config: SSL_CPPFLAGS: "-I/usr/local/ssl/include "
    checking for HMAC_Update in -lcrypto... yes
    checking OpenSSL linking without -ldl... yes
    checking for SSL_connect in -lssl... yes
    checking openssl/x509.h usability... yes
    checking openssl/x509.h presence... yes
    checking for openssl/x509.h... yes
    checking openssl/rsa.h usability... yes
    checking openssl/rsa.h presence... yes
    checking for openssl/rsa.h... yes
    checking openssl/crypto.h usability... yes
    checking openssl/crypto.h presence... yes
    checking for openssl/crypto.h... yes
    checking openssl/pem.h usability... yes
    checking openssl/pem.h presence... yes
    checking for openssl/pem.h... yes
    checking openssl/ssl.h usability... yes
    checking openssl/ssl.h presence... yes
    checking for openssl/ssl.h... yes
    checking openssl/err.h usability... yes
    checking openssl/err.h presence... yes
    checking for openssl/err.h... yes
    checking openssl/pkcs12.h usability... yes
    checking openssl/pkcs12.h presence... yes
    checking for openssl/pkcs12.h... yes
    checking for ENGINE_init... yes
    checking openssl/engine.h usability... yes
    checking openssl/engine.h presence... yes
    checking for openssl/engine.h... yes
    checking for ENGINE_load_builtin_engines... yes
    checking for RAND_status... yes
    checking for RAND_screen... no
    checking for RAND_egd... yes
    checking for ENGINE_cleanup... yes
    checking for CRYPTO_cleanup_all_ex_data... yes
    checking for SSL_get_shutdown... yes
    checking for SSLv2_client_method... no
    checking for DES_set_odd_parity... yes
    checking for BoringSSL... no
    checking for libressl... no
    configure: Added /usr/local/ssl/lib64 to LD_LIBRARY_PATH
    checking for OpenSSL headers version... unknown
    checking for OpenSSL library version... 1.0.2
>>> checking for OpenSSL headers and library versions matching... fail
    ...

[jay]

That's from m4/curl-openssl.m4. Based on that output you don't have a curl_cv_have_def_OPENSSL_VERSION_NUMBER. Check your config.log for #define USE_OPENSSL 1 and #define HAVE_OPENSSL_CRYPTO_H 1 , based on the output you should have both. Are sed and grep working? Check config.log for "checking for OpenSSL headers version" see if there's anything telling there esp -I , also check opensslv.h which is where OPENSSL_VERSION_NUMBER should be defined like # define OPENSSL_VERSION_NUMBER 0x1000207fL

hi,

That's from curl/curl-openssl.m4. Based on that output you don't have a curl_cv_have_def_OPENSSL_VERSION_NUMBER.

Check your config.log for #define USE_OPENSSL 1 and #define HAVE_OPENSSL_CRYPTO_H 1 , based on the output you should have both.

grep "^[ ].*#define USE_OPENSSL" config.log
    #define USE_OPENSSL 1
    #define USE_OPENSSL 1
    #define USE_OPENSSL 1
    #define USE_OPENSSL 1
    #define USE_OPENSSL 1
    #define USE_OPENSSL 1

grep "^[ ]*#define HAVE_OPENSSL_CRYPTO_H 1" config.log
    #define HAVE_OPENSSL_CRYPTO_H 1

Are sed and grep working?

yep

grep --version | head -n 1
    grep (GNU grep) 2.16
sed --version | head -n 1
    sed (GNU sed) 4.2.2

Check config.log for "checking for OpenSSL headers version" see if there's anything telling there esp -I ,

    -------------------
    ...
    configure:22515: result: no
    configure:22527: Added /usr/local/ssl/lib64 to LD_LIBRARY_PATH
>>>    configure:22537: checking for OpenSSL headers version
    configure:22564: /usr/bin/gcc-5 -E -isystem /usr/local/ssl/include -isystem /usr/include -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -I/usr/local/ssl/include  conftest.c
    configure:22564: $? = 0
    configure:22624: result: unknown
    configure:22633: checking for OpenSSL library version
    configure:22701: /usr/bin/gcc-5 -o conftest -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -Wno-system-headers -isystem /usr/local/ssl/include -isystem /usr/include -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -I/usr/local/ssl/include   -L/usr/local/ssl/lib64  -Wl,-rpath,/usr/local/ssl/lib64  -L/usr/local/lib64 -L/usr/local/lib64 -Wl,-rpath,/usr/local/lib64 -L/usr/local/ssl/lib64  conftest.c -lssl -lcrypto -lssl -lcrypto  -lz  -lssl -lcrypto  -lssh2 >&5
    /tmp/ccle8B8g.o: In function `main':
    conftest.c:(.text.startup+0x7): undefined reference to `SSL_CTX_set_not_resumable_session_callback'
    collect2: error: ld returned 1 exit status
    configure:22701: $? = 1
    configure: failed program was:
    | /* confdefs.h */
    | #define PACKAGE_NAME "curl"
    | #define PACKAGE_TARNAME "curl"
    | #define PACKAGE_VERSION "-"
    | #define PACKAGE_STRING "curl -"
    | #define PACKAGE_BUGREPORT "a suitable curl mailing list: https://curl.haxx.se/mail/"
    | #define PACKAGE_URL ""
    | #define PACKAGE "curl"
    | #define VERSION "-"
    | #define OS "x86_64-suse-linux-gnu"
    | #define HAVE_SYS_TYPES_H 1
    | #define HAVE_STDINT_H 1
    | #define HAVE_INTTYPES_H 1
    | #define STDC_HEADERS 1
    | #define HAVE_SYS_TYPES_H 1
    | #define HAVE_SYS_STAT_H 1
    | #define HAVE_STDLIB_H 1
    | #define HAVE_STRING_H 1
    | #define HAVE_MEMORY_H 1
    | #define HAVE_STRINGS_H 1
    | #define HAVE_INTTYPES_H 1
    | #define HAVE_STDINT_H 1
    | #define HAVE_UNISTD_H 1
    | #define SIZEOF_LONG 8
    | #define SIZEOF_VOIDP 8
    | #define CURL_TYPEOF_CURL_OFF_T long
    | #define CURL_FORMAT_CURL_OFF_T "ld"
    | #define CURL_FORMAT_CURL_OFF_TU "lu"
    | #define CURL_FORMAT_OFF_T "%ld"
    | #define CURL_SIZEOF_CURL_OFF_T 8
    | #define CURL_SUFFIX_CURL_OFF_T L
    | #define CURL_SUFFIX_CURL_OFF_TU UL
    | #define HAVE_DLFCN_H 1
    | #define LT_OBJDIR ".libs/"
    | #define CURL_DISABLE_LDAP 1
    | #define CURL_DISABLE_LDAPS 1
    | #define TIME_WITH_SYS_TIME 1
    | #define HAVE_SYS_TYPES_H 1
    | #define HAVE_SYS_TIME_H 1
    | #define HAVE_TIME_H 1
    | #define HAVE_CLOCK_GETTIME_MONOTONIC 1
    | #define HAVE_ZLIB_H 1
    | #define HAVE_LIBZ 1
    | #define HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID 1
    | #define HAVE_WRITABLE_ARGV 1
    | #define HAVE_LIBSSL 1
    | #define HAVE_OPENSSL_X509_H 1
    | #define USE_OPENSSL 1
    | #define HAVE_OPENSSL_RSA_H 1
    | #define USE_OPENSSL 1
    | #define HAVE_OPENSSL_CRYPTO_H 1
    | #define USE_OPENSSL 1
    | #define HAVE_OPENSSL_PEM_H 1
    | #define USE_OPENSSL 1
    | #define HAVE_OPENSSL_SSL_H 1
    | #define USE_OPENSSL 1
    | #define HAVE_OPENSSL_ERR_H 1
    | #define USE_OPENSSL 1
    | #define HAVE_OPENSSL_PKCS12_H 1
    | #define HAVE_OPENSSL_ENGINE_H 1
    | #define HAVE_ENGINE_LOAD_BUILTIN_ENGINES 1
    | #define HAVE_RAND_STATUS 1
    | #define HAVE_RAND_EGD 1
    | #define HAVE_ENGINE_CLEANUP 1
    | #define HAVE_CRYPTO_CLEANUP_ALL_EX_DATA 1
    | #define HAVE_SSL_GET_SHUTDOWN 1
    | #define HAVE_DES_SET_ODD_PARITY 1
    | /* end confdefs.h.  */
    | 
    | 
    | #define SSL_CTX_set_not_resumable_session_callback innocuous_SSL_CTX_set_not_resumable_session_callback
    | #ifdef __STDC__
    | # include <limits.h>
    | #else
    | # include <assert.h>
    | #endif
    | #undef SSL_CTX_set_not_resumable_session_callback
    | #ifdef __cplusplus
    | extern "C"
    | #endif
    | char SSL_CTX_set_not_resumable_session_callback ();
    | #if defined __stub_SSL_CTX_set_not_resumable_session_callback || defined __stub___SSL_CTX_set_not_resumable_session_callback
    | choke me
    | #endif
    | 
    | int main (void)
    | {
    | return SSL_CTX_set_not_resumable_session_callback ();
    |  ;
    |  return 0;
    | }
    | 
    configure:22739: /usr/bin/gcc-5 -o conftest -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -Wno-system-headers -isystem /usr/local/ssl/include -isystem /usr/include -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -I/usr/local/ssl/include   -L/usr/local/ssl/lib64  -Wl,-rpath,/usr/local/ssl/lib64  -L/usr/local/lib64 -L/usr/local/lib64 -Wl,-rpath,/usr/local/lib64 -L/usr/local/ssl/lib64  conftest.c -lssl -lcrypto -lssl -lcrypto  -lz  -lssl -lcrypto  -lssh2 >&5
    configure:22739: $? = 0
    configure:23123: result: 1.0.2
    configure:23131: checking for OpenSSL headers and library versions matching
    configure:23141: result: fail
    configure:23144: WARNING: Can not compare OpenSSL headers and library versions.
    configure:23177: checking for "/dev/urandom"
    configure:23191: result: yes
    configure:23216: checking for SRP_Calc_client_key in -lcrypto
    configure:23238: /usr/bin/gcc-5 -o conftest -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -Wno-system-headers -isystem /usr/local/ssl/include -isystem /usr/include -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -I/usr/local/ssl/include   -L/usr/local/ssl/lib64  -Wl,-rpath,/usr/local/ssl/lib64  -L/usr/local/lib64 -L/usr/local/lib64 -Wl,-rpath,/usr/local/lib64 -L/usr/local/ssl/lib64  conftest.c -lcrypto  -lssl -lcrypto -lssl -lcrypto  -lz  -lssl -lcrypto  -lssh2 >&5
    configure:23238: $? = 0
    configure:23247: result: yes
    configure:24923: checking default CA cert bundle/path
    configure:25022: result: /etc/ssl/certs/ (capath)
    configure:25041: checking for library containing psl_builtin
    configure:25069: /usr/bin/gcc-5 -o conftest -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -Wno-system-headers -isystem /usr/local/ssl/include -isystem /usr/include -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -I/usr/local/ssl/include   -L/usr/local/ssl/lib64  -Wl,-rpath,/usr/local/ssl/lib64  -L/usr/local/lib64 -L/usr/local/lib64 -Wl,-rpath,/usr/local/lib64 -L/usr/local/ssl/lib64  conftest.c -lssl -lcrypto -lssl -lcrypto  -lz  -lssl -lcrypto  -lssh2 >&5
    /tmp/ccojbLuv.o: In function `main':
    conftest.c:(.text.startup+0x7): undefined reference to `psl_builtin'
    collect2: error: ld returned 1 exit status
    configure:25069: $? = 1
    configure: failed program was:
    | /* confdefs.h */
    | #define PACKAGE_NAME "curl"
    | #define PACKAGE_TARNAME "curl"
    | #define PACKAGE_VERSION "-"
    | #define PACKAGE_STRING "curl -"
    | #define PACKAGE_BUGREPORT "a suitable curl mailing list: https://curl.haxx.se/mail/"
    | #define PACKAGE_URL ""
    | #define PACKAGE "curl"
    | #define VERSION "-"
    | #define OS "x86_64-suse-linux-gnu"
    | #define HAVE_SYS_TYPES_H 1
    | #define HAVE_STDINT_H 1
    | #define HAVE_INTTYPES_H 1
    | #define STDC_HEADERS 1
    | #define HAVE_SYS_TYPES_H 1
    | #define HAVE_SYS_STAT_H 1
    | #define HAVE_STDLIB_H 1
    | #define HAVE_STRING_H 1
    | #define HAVE_MEMORY_H 1
    | #define HAVE_STRINGS_H 1
    | #define HAVE_INTTYPES_H 1
    | #define HAVE_STDINT_H 1
    | #define HAVE_UNISTD_H 1
    | #define SIZEOF_LONG 8
    | #define SIZEOF_VOIDP 8
    | #define CURL_TYPEOF_CURL_OFF_T long
    | #define CURL_FORMAT_CURL_OFF_T "ld"
    | #define CURL_FORMAT_CURL_OFF_TU "lu"
    | #define CURL_FORMAT_OFF_T "%ld"
    | #define CURL_SIZEOF_CURL_OFF_T 8
    | #define CURL_SUFFIX_CURL_OFF_T L
    | #define CURL_SUFFIX_CURL_OFF_TU UL
    | #define HAVE_DLFCN_H 1
    | #define LT_OBJDIR ".libs/"
    | #define CURL_DISABLE_LDAP 1
    | #define CURL_DISABLE_LDAPS 1
    | #define TIME_WITH_SYS_TIME 1
    | #define HAVE_SYS_TYPES_H 1
    | #define HAVE_SYS_TIME_H 1
    | #define HAVE_TIME_H 1
    | #define HAVE_CLOCK_GETTIME_MONOTONIC 1
    | #define HAVE_ZLIB_H 1
    | #define HAVE_LIBZ 1
    | #define HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID 1
    | #define HAVE_WRITABLE_ARGV 1
    | #define HAVE_LIBSSL 1
    | #define HAVE_OPENSSL_X509_H 1
    | #define USE_OPENSSL 1
    | #define HAVE_OPENSSL_RSA_H 1
    | #define USE_OPENSSL 1
    | #define HAVE_OPENSSL_CRYPTO_H 1
    | #define USE_OPENSSL 1
    | #define HAVE_OPENSSL_PEM_H 1
    | #define USE_OPENSSL 1
    | #define HAVE_OPENSSL_SSL_H 1
    | #define USE_OPENSSL 1
    | #define HAVE_OPENSSL_ERR_H 1
    | #define USE_OPENSSL 1
    | #define HAVE_OPENSSL_PKCS12_H 1
    | #define HAVE_OPENSSL_ENGINE_H 1
    | #define HAVE_ENGINE_LOAD_BUILTIN_ENGINES 1
    | #define HAVE_RAND_STATUS 1
    | #define HAVE_RAND_EGD 1
    | #define HAVE_ENGINE_CLEANUP 1
    | #define HAVE_CRYPTO_CLEANUP_ALL_EX_DATA 1
    | #define HAVE_SSL_GET_SHUTDOWN 1
    | #define HAVE_DES_SET_ODD_PARITY 1
    | #define RANDOM_FILE "/dev/urandom"
    | #define HAVE_OPENSSL_SRP 1
    | #define CURL_CA_PATH "/etc/ssl/certs/"
    | /* end confdefs.h.  */
    | 
    ...
    -------------------

also check opensslv.h which is where OPENSSL_VERSION_NUMBER should be defined like # define OPENSSL_VERSION_NUMBER 0x1000207fL

grep OPENSSL_VERSION_NUMBER /usr/local/ssl/include/openssl/opensslv.h
    # define OPENSSL_VERSION_NUMBER  0x1000207fL

[jay]

I don't see anything unusual there. It's probably failing to parse. Can you save a copy of the conftest file that is used to get the version number? This way we can go step by step to figure out what the problem is. Apply this:

diff --git a/acinclude.m4 b/acinclude.m4
index 4f25ac6..0f21624 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -56,6 +56,9 @@ CURL_DEF_TOKEN $1
     if test -z "$tmp_exp" || test "$tmp_exp" = "$1"; then
       tmp_exp=""
     fi
+    if test "x$1" = "xOPENSSL_VERSION_NUMBER"; then
+      cp conftest.$ac_ext osslver.c
+    fi
   ])
   if test -z "$tmp_exp"; then
     AS_VAR_SET(ac_HaveDef, no)

Use ./buildconf to regenerate then ./configure same way you did before. Check that the result is the same. You should now have a osslver.c file. Try to parse it manually using the same method configure should be using:

gcc -E -isystem /usr/local/include -isystem /usr/include -O3 \
  -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables \
  -grecord-gcc-switches -march=native -mtune=native \
  -fasynchronous-unwind-tables -fmessage-length=0 \
  -I/usr/local/ssl/include \
  osslver.c | \
grep CURL_DEF_TOKEN | \
sed 's/.*CURL_DEF_TOKEN[ ][ ]*//' | \
sed 's/["][ ]*["]//g'

The expected output is 0x1000207fL. If not judge from any error messages and step back until you figure it out.

The expected output is 0x1000207fL.

and so it is ... :-/

cd curl
git branch -a | grep \*
    * curl-7_47_1
git clean -xfd
git reset --hard
    HEAD is now at 8f995e2 RELEASE-NOTES: curl 7.47.1 time!

cat /usr/local/src/libcurl-openssl.patch
    diff --git a/acinclude.m4 b/acinclude.m4
    index 4f25ac6..0f21624 100644
    --- a/acinclude.m4
    +++ b/acinclude.m4
    @@ -56,6 +56,9 @@ CURL_DEF_TOKEN $1
         if test -z "$tmp_exp" || test "$tmp_exp" = "$1"; then
           tmp_exp=""
         fi
    +    if test "x$1" = "xOPENSSL_VERSION_NUMBER"; then
    +      cp conftest.$ac_ext osslver.c
    +    fi
       ])
       if test -z "$tmp_exp"; then
         AS_VAR_SET(ac_HaveDef, no)

patch -p1 < /usr/local/src/libcurl-openssl.patch
    patching file acinclude.m4

echo $LDFLAGS
    -L/usr/local/ssl/lib64 -Wl,-rpath,/usr/local/ssl/lib64 -L/usr/local/lib64 -L/usr/local/lib64 -Wl,-rpath,/usr/local/lib64
echo $LIBS
    -lssl -lcrypto -lssh2

./buildconf
./configure --with-ssl

cat osslver.c
    /* confdefs.h */
    #define PACKAGE_NAME "curl"
    #define PACKAGE_TARNAME "curl"
    #define PACKAGE_VERSION "-"
    #define PACKAGE_STRING "curl -"
    #define PACKAGE_BUGREPORT "a suitable curl mailing list: https://curl.haxx.se/mail/"
    #define PACKAGE_URL ""
    #define PACKAGE "curl"
    #define VERSION "-"
    #define OS "x86_64-suse-linux-gnu"
    #define HAVE_SYS_TYPES_H 1
    #define HAVE_STDINT_H 1
    #define HAVE_INTTYPES_H 1
    #define STDC_HEADERS 1
    #define HAVE_SYS_TYPES_H 1
    #define HAVE_SYS_STAT_H 1
    #define HAVE_STDLIB_H 1
    #define HAVE_STRING_H 1
    #define HAVE_MEMORY_H 1
    #define HAVE_STRINGS_H 1
    #define HAVE_INTTYPES_H 1
    #define HAVE_STDINT_H 1
    #define HAVE_UNISTD_H 1
    #define SIZEOF_LONG 8
    #define SIZEOF_VOIDP 8
    #define CURL_TYPEOF_CURL_OFF_T long
    #define CURL_FORMAT_CURL_OFF_T "ld"
    #define CURL_FORMAT_CURL_OFF_TU "lu"
    #define CURL_FORMAT_OFF_T "%ld"
    #define CURL_SIZEOF_CURL_OFF_T 8
    #define CURL_SUFFIX_CURL_OFF_T L
    #define CURL_SUFFIX_CURL_OFF_TU UL
    #define HAVE_DLFCN_H 1
    #define LT_OBJDIR ".libs/"
    #define HAVE_LDAP_SSL 1
    #define TIME_WITH_SYS_TIME 1
    #define HAVE_SYS_TYPES_H 1
    #define HAVE_SYS_TIME_H 1
    #define HAVE_TIME_H 1
    #define HAVE_CLOCK_GETTIME_MONOTONIC 1
    #define HAVE_ZLIB_H 1
    #define HAVE_LIBZ 1
    #define HAVE_LBER_H 1
    #define HAVE_LDAP_H 1
    #define HAVE_LDAP_URL_PARSE 1
    #define HAVE_LDAP_INIT_FD 1
    #define USE_OPENLDAP 1
    #define HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID 1
    #define HAVE_WRITABLE_ARGV 1
    #define HAVE_LIBSSL 1
    #define HAVE_OPENSSL_X509_H 1
    #define USE_OPENSSL 1
    #define HAVE_OPENSSL_RSA_H 1
    #define USE_OPENSSL 1
    #define HAVE_OPENSSL_CRYPTO_H 1
    #define USE_OPENSSL 1
    #define HAVE_OPENSSL_PEM_H 1
    #define USE_OPENSSL 1
    #define HAVE_OPENSSL_SSL_H 1
    #define USE_OPENSSL 1
    #define HAVE_OPENSSL_ERR_H 1
    #define USE_OPENSSL 1
    #define HAVE_OPENSSL_PKCS12_H 1
    #define HAVE_OPENSSL_ENGINE_H 1
    #define HAVE_ENGINE_LOAD_BUILTIN_ENGINES 1
    #define HAVE_RAND_STATUS 1
    #define HAVE_RAND_EGD 1
    #define HAVE_ENGINE_CLEANUP 1
    #define HAVE_CRYPTO_CLEANUP_ALL_EX_DATA 1
    #define HAVE_SSL_GET_SHUTDOWN 1
    #define HAVE_DES_SET_ODD_PARITY 1
    /* end confdefs.h.  */


    #   ifdef USE_OPENSSL
    #     include <openssl/crypto.h>
    #   else
    #     include <crypto.h>
    #   endif

    #ifdef OPENSSL_VERSION_NUMBER
    CURL_DEF_TOKEN OPENSSL_VERSION_NUMBER
    #endif

gcc -E -isystem /usr/local/include -isystem /usr/include -O3 \
  -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables \
  -grecord-gcc-switches -march=native -mtune=native \
  -fasynchronous-unwind-tables -fmessage-length=0 \
  -I/usr/local/ssl/include \
  osslver.c | \
grep CURL_DEF_TOKEN | \
sed 's/.*CURL_DEF_TOKEN[ ][ ]*//' | \
sed 's/["][ ]*["]//g'

    0x1000207fL

Note, however, that is NOT the cmd string from above. Rather, this is:

/usr/bin/gcc-5 -E -isystem /usr/local/ssl/include -isystem /usr/include -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -I/usr/local/ssl/include  conftest.c

Exec'ing that against the saved osslver.c

/usr/bin/gcc-5 -E -isystem /usr/local/ssl/include -isystem /usr/include -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -I/usr/local/ssl/include  \
  osslver.c | \
grep CURL_DEF_TOKEN | \
sed 's/.*CURL_DEF_TOKEN[ ][ ]*//' | \
sed 's/["][ ]*["]//g'

returns

(null)

, nothing.

[jay]

might be gcc-5 , walk it back like

/usr/bin/gcc-5 -E -isystem /usr/local/ssl/include -isystem /usr/include -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -I/usr/local/ssl/include \
  osslver.c | \
grep CURL_DEF_TOKEN | \
sed 's/.*CURL_DEF_TOKEN[ ][ ]*//' | \
sed 's/["][ ]*["]//g'

/usr/bin/gcc-5 -E -isystem /usr/local/ssl/include -isystem /usr/include -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -I/usr/local/ssl/include  \
  osslver.c | \
grep CURL_DEF_TOKEN | \
sed 's/.*CURL_DEF_TOKEN[ ][ ]*//'

/usr/bin/gcc-5 -E -isystem /usr/local/ssl/include -isystem /usr/include -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -I/usr/local/ssl/include  \
  osslver.c | \
grep CURL_DEF_TOKEN

/usr/bin/gcc-5 -E -isystem /usr/local/ssl/include -isystem /usr/include -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -I/usr/local/ssl/include  \
  osslver.c

As before

git clean -xfd
git reset --hard
patch -p1 < /usr/local/src/libcurl-openssl.patch
./buildconf
./configure --with-ssl

the walk-back

/usr/bin/gcc-5 -E -isystem /usr/local/ssl/include -isystem /usr/include -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -I/usr/local/ssl/include \
  osslver.c | \
grep CURL_DEF_TOKEN | \
sed 's/.*CURL_DEF_TOKEN[ ][ ]*//' | \
sed 's/["][ ]*["]//g'

    (empty)

/usr/bin/gcc-5 -E -isystem /usr/local/ssl/include -isystem /usr/include -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -I/usr/local/ssl/include  \
  osslver.c | \
grep CURL_DEF_TOKEN | \
sed 's/.*CURL_DEF_TOKEN[ ][ ]*//'

    (empty)

/usr/bin/gcc-5 -E -isystem /usr/local/ssl/include -isystem /usr/include -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -I/usr/local/ssl/include  \
  osslver.c | \
grep CURL_DEF_TOKEN

    CURL_DEF_TOKEN 

/usr/bin/gcc-5 -E -isystem /usr/local/ssl/include -isystem /usr/include -O3 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches -march=native -mtune=native -I/usr/local/ssl/include  \
  osslver.c

-->
output at pastebin (or this attachment)

So, can certainly see where it's going 'empty'. I'll have to stare it a bit to figure out the expected behavior ...

[jay]

The preprocessor output for gcc 4 looks like this:

# 87 "osslver.c" 2
[some blank lines]
CURL_DEF_TOKEN 0x1000207fL

Yours looks like:

# 82 "osslver.c"
CURL_DEF_TOKEN 
# 82 "osslver.c" 3 4
              0x1000207fL

This exact issue is described in GCC 5 porting issues. Try adding the -P option to remove linemarkers and see what that gives you.

adding

export CPPFLAGS+=" -P"

appears to cure the config issue

./buildconf
./configure ...
    ...
    configure: Added /usr/local/ssl/lib64 to LD_LIBRARY_PATH
    checking for OpenSSL headers version... 1.0.2 - 0x1000207fL
    checking for OpenSSL library version... 1.0.2
    checking for OpenSSL headers and library versions matching... yes
    ...

hat's off - nice catch!

Given that gcc5's long been in release, and as

https://gcc.gnu.org/gcc-5/porting_to.html
"These new markers can cause intriguing problems for software not ready to handle them."

should this issue be re-branded as a "port build to gcc5" bug?

[bagder]

... and I've been using gcc5 on my systems for years without ever having this problem, and I build curl may times every day. What Linux distro and version is this?

of course it works for you ;-)

This is Opensuse Leap

lsb_release -rd
    Description:    openSUSE Leap 42.1 (x86_64)
    Release:        42.1

With GCC 5

gcc -v
    Using built-in specs.
    COLLECT_GCC=gcc
    COLLECT_LTO_WRAPPER=/usr/lib64/gcc/x86_64-suse-linux/5/lto-wrapper
    Target: x86_64-suse-linux
    Configured with: ../configure --prefix=/usr --infodir=/usr/share/info --mandir=/usr/share/man --libdir=/usr/lib64 --libexecdir=/usr/lib64 --enable-languages=c,c++,objc,fortran,obj-c++,java,ada,go --enable-checking=release --with-gxx-include-dir=/usr/include/c++/5 --enable-ssp --disable-libssp --disable-libvtv --enable-libmpx --disable-plugin --with-bugurl=http://bugs.opensuse.org/ --with-pkgversion='SUSE Linux' --disable-libgcj --with-slibdir=/lib64 --with-system-zlib --enable-__cxa_atexit --enable-libstdcxx-allocator=new --disable-libstdcxx-pch --with-default-libstdcxx-abi=gcc4-compatible --enable-version-specific-runtime-libs --enable-linker-build-id --enable-linux-futex --program-suffix=-5 --without-system-libunwind --enable-multilib --with-arch-32=x86-64 --with-tune=generic --build=x86_64-suse-linux --host=x86_64-suse-linux
    Thread model: posix
    gcc version 5.3.1 20160301 [gcc-5-branch revision 233849] (SUSE Linux) 

tracked from the project's dev repo

http://download.opensuse.org/repositories/devel:/gcc/openSUSE_Leap_42.1

[bagder]

I also have gcc 5.3.1, but looking at my configure output closer it actually says:

checking for OpenSSL headers version... unknown
checking for OpenSSL library version... 1.0.2
checking for OpenSSL headers and library versions matching... fail
configure: WARNING: Can not compare OpenSSL headers and library versions.

and with the "-P" added to your CPPFLAGS ... ?

[bagder]

Yeah, I can fix the script with -P. I guess I just need to make sure the preprocessor actually supports -P first before using it...

diff --git a/acinclude.m4 b/acinclude.m4
index 4f25ac6..e993e1e 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -29,10 +29,12 @@ dnl includes even if no INCLUDES argument is given. This macro will run
 dnl silently when invoked with three arguments. If the expansion would
 dnl result in a set of double-quoted strings the returned expansion will
 dnl actually be a single double-quoted string concatenating all them.

 AC_DEFUN([CURL_CHECK_DEF], [
+  OLDCPPFLAGS=$CPPFLAGS
+  CPPFLAGS="$CPPFLAGS -P"
   AS_VAR_PUSHDEF([ac_HaveDef], [curl_cv_have_def_$1])dnl
   AS_VAR_PUSHDEF([ac_Def], [curl_cv_def_$1])dnl
   if test -z "$SED"; then
     AC_MSG_ERROR([SED not set. Cannot continue without SED being set.])
   fi
@@ -65,10 +67,11 @@ CURL_DEF_TOKEN $1
     AS_VAR_SET(ac_Def, $tmp_exp)
     ifelse($3,,[AC_MSG_RESULT([$tmp_exp])])
   fi
   AS_VAR_POPDEF([ac_Def])dnl
   AS_VAR_POPDEF([ac_HaveDef])dnl
+  CPPFLAGS=$OLDCPPFLAGS
 ])


 dnl CURL_CHECK_DEF_CC (SYMBOL, [INCLUDES], [SILENT])
 dnl -------------------------------------------------