Error building curl with openssl via pkgconfig

[pszemus]

I did this

PKG_CONFIG_PATH=/opt/WP/common.libs/lib/pkgconfig ./configure --with-ssl

I expected the following

Curl will be configured to build with SSL support.
OpenSSL is installed in custom path.

what happened

configure script does not report SSL (HTTPS, FTPS, ...) support:

configure: Configured to build curl/libcurl:

  curl version:     7.61.0
  SSL support:      no
  Protocols:        DICT FILE FTP GOPHER HTTP IMAP POP3 RTSP SMTP TELNET TFTP

OpenSSL static libraries are installed in custom path via ./config --prefix=/opt/WP/common.libs --openssldir=/opt/WP/common.libs no-shared -fPIC
pkgconfig files are also installed in /opt/WP/common.libs/lib/pkgconfig/libssl.pc:

prefix=/opt/WP/common.libs
exec_prefix=${prefix}
libdir=${exec_prefix}/lib
includedir=${prefix}/include

Name: OpenSSL-libssl
Description: Secure Sockets Layer and cryptography libraries
Version: 1.1.0h
Requires.private: libcrypto
Libs: -L${libdir} -lssl
Cflags: -I${includedir}

curl's config.log shows missing 'pthread':

configure:22454: checking for openssl options with pkg-config
configure:22468: result: found
configure:22497: pkg-config: SSL_LIBS: "-lssl -lcrypto  "
configure:22499: pkg-config: SSL_LDFLAGS: "-L/opt/WP/common.libs/lib  "
configure:22501: pkg-config: SSL_CPPFLAGS: "-I/opt/WP/common.libs/include  "
configure:22513: checking for HMAC_Update in -lcrypto
configure:22535: gcc -o conftest -Werror-implicit-function-declaration -O2 -Wno-system-headers    -I/opt/WP/common.libs/include      -L/opt/WP/common.libs/lib   conftest.c -lcrypto  -lssl -lcrypto   -lz  >&5
/opt/WP/common.libs/lib/libcrypto.a(threads_pthread.o): In function `CRYPTO_THREAD_lock_new':
threads_pthread.c:(.text+0x25): undefined reference to `pthread_rwlock_init'

curl/libcurl version

curl-7.61.0

operating system

openssl-1.1.0h
CentOS Linux release 7.5.1804 (Core)

[bagder]

If you look in your config.log below that snippet you showed here, you'll see that configure goes on and then tries again with -ldl and then with -ldl -lpthread added...

In the latter case, the error message it gets back says:

conftest.c:36:21: fatal error: openssl/err.h: No such file or directory
            #include <openssl/err.h>
                     ^~~~~~~~~~~~~~~

It looks like you have a bad openssl install? That's a standard openssl header that's been around since basically forever.

This seems to happen because the AC_TRY_LINK that is tested uses #include and yet the command line that builds the test program didn't get your -I/opt/WP/common.libs/include from the pkg-config...

[bagder]

Maybe a patch like this?

diff --git a/configure.ac b/configure.ac
index 22280a5e9..b20ce13de 100755
--- a/configure.ac
+++ b/configure.ac
@@ -1648,11 +1648,14 @@ if test -z "$ssl_backends" -o "x$OPT_SSL" != xno &&
   AC_CHECK_LIB(crypto, HMAC_Update,[
      HAVECRYPTO="yes"
      LIBS="-lcrypto $LIBS"
      ],[
      LDFLAGS="$CLEANLDFLAGS -L$LIB_OPENSSL"
-     CPPFLAGS="$CLEANCPPFLAGS -I$PREFIX_OPENSSL/include/openssl -I$PREFIX_OPENSSL/include"
+     if test "$PKGCONFIG" != "yes" ; then
+       # only set this if pkg-config wasn't used
+       CPPFLAGS="$CLEANCPPFLAGS -I$PREFIX_OPENSSL/include/openssl -I$PREFIX_OPENSSL/include"
+     fi
      AC_CHECK_LIB(crypto, HMAC_Init_ex,[
        HAVECRYPTO="yes"
        LIBS="-lcrypto $LIBS"], [
 
        dnl still no, but what about with -ldl?

[pszemus]

I'd change it to:

diff --git a/configure.ac b/configure.ac
index 22280a5e9..b20ce13de 100755
--- a/configure.ac
+++ b/configure.ac
@@ -1648,11 +1648,14 @@ if test -z "$ssl_backends" -o "x$OPT_SSL" != xno &&
   AC_CHECK_LIB(crypto, HMAC_Update,[
      HAVECRYPTO="yes"
      LIBS="-lcrypto $LIBS"
      ],[
      LDFLAGS="$CLEANLDFLAGS -L$LIB_OPENSSL"
-     CPPFLAGS="$CLEANCPPFLAGS -I$PREFIX_OPENSSL/include/openssl -I$PREFIX_OPENSSL/include"
+     if test "$PKGCONFIG" = "no" ; then
+       # only set this if pkg-config wasn't used
+       CPPFLAGS="$CLEANCPPFLAGS -I$PREFIX_OPENSSL/include/openssl -I$PREFIX_OPENSSL/include"
+     fi
      AC_CHECK_LIB(crypto, HMAC_Init_ex,[
        HAVECRYPTO="yes"
        LIBS="-lcrypto $LIBS"], [
 
        dnl still no, but what about with -ldl?

because PKGCONFIG variable can be "no" or "/usr/bin/pkg-config", to the best of my knowledge.

The aforementioned patch works.

[bagder]

Excellent!