make error when multi version of openssl library installed in system

[buaazp]

If you installed more than one version of openssl library. CmakeList.txt in zimg cannot fit it correctly.
For example, CentOS has a low version openssl (found version "0.9.8e-rhel5") which cannot be used for build libevhtp. Then you install a new openssl by sourcecode. Error happens like this:

Scanning dependencies of target zimg
Linking C executable zimg
/usr/bin/ld: skipping incompatible /usr/lib/libssl.so when searching for -lssl
/usr/bin/ld: skipping incompatible /usr/lib/libssl.a when searching for -lssl
/usr/bin/ld: skipping incompatible /usr/lib/libcrypto.so when searching for -lcrypto
/usr/bin/ld: skipping incompatible /usr/lib/libcrypto.a when searching for -lcrypto
/usr/bin/ld: skipping incompatible /usr/lib/liblua-5.1.so when searching for -llua-5.1
/usr/bin/ld: skipping incompatible /usr/lib/libm.so when searching for -lm
/usr/bin/ld: skipping incompatible /usr/lib/libm.a when searching for -lm
/usr/bin/ld: skipping incompatible /usr/lib/libpthread.so when searching for -lpthread
/usr/bin/ld: skipping incompatible /usr/lib/libpthread.a when searching for -lpthread
/usr/bin/ld: skipping incompatible /usr/lib/libc.so when searching for -lc
/usr/bin/ld: skipping incompatible /usr/lib/libc.a when searching for -lc
/usr/local/lib/libevhtp.a(evhtp.c.o): In function `evhtp_ssl_init':
evhtp.c:(.text+0x1018): undefined reference to `EC_KEY_new_by_curve_name'
evhtp.c:(.text+0x1040): undefined reference to `EC_KEY_free'
/usr/local/lib/libevhtp.a(evhtp.c.o): In function `_evhtp_ssl_servername':
evhtp.c:(.text+0x4f7e): undefined reference to `SSL_get_servername'
evhtp.c:(.text+0x501c): undefined reference to `SSL_set_SSL_CTX'
/usr/local/lib/libevhtp.a(evhtp.c.o): In function `_evhtp_request_parser_hostname':
evhtp.c:(.text+0x5c99): undefined reference to `SSL_get_servername'
collect2: ld returned 1 exit status
make[2]: *** [zimg] Error 1
make[1]: *** [CMakeFiles/zimg.dir/all] Error 2
make: *** [all] Error 2

[buaazp]

The reason of this bug is cmake function find_package(OpenSSL) can only find the low version openssl and it conflicts with libevhtp.a.

To fix this problem, take steps below:

1.find the path of high version openssl, in my system is:

/usr/local/lib64/libssl.a
/usr/local/lib64/libcrypto.a

2.modify vim CMakeLists.txt and added this path to the CMAKE_EXE_LINKER_FLAGS. Make sure this path is front than others. The postion of CMAKE_EXE_LINKER_FLAGS is at the end of CMakeLists.txt:

set(CMAKE_EXE_LINKER_FLAGS "-L/usr/local/lib64 -L/usr/local/lib -L/usr/lib")

3.rebuild zimg will succ.

cmake .
make

[errzey]

You can also do:

 LDFLAGS="-L/usr/local/lib64 -L/usr/local/lib -L/usr/lib" cmake .

[buaazp]

Got it!
Thanks @ellzey