./configure --with-openssl fails with OpenSSL 1.1, SSL_library_init now a macro

[Luo2Jie2]

When running ./configure --with-openssl on Debian Stretch. The ./configure output ends with

checking for OpenSSL version via pkg-config... 1.1.0f found
checking for OpenSSL cflags...
checking for OpenSSL ldflags... -lssl -lcrypto
checking for openssl/ssl.h... yes
checking for SSL_library_init... no
configure: error: "OpenSSL not found, required for SSL support"

File ssl.h which defines SSL_library_init is present, but configure can't see the
symbol SSL_library_init.

Quoting https://bugs.archlinux.org/task/53809 << in openssl 1.1,
SSL_library_init is a preprocessor macro, not an actual symbol; so
libesmtp's ./configure erroneously thinks that libssl isn't available, >>

Roger

[Luo2Jie2]

Workaround (not very elegant):
Look in script configure for the two lines which declare
if test "x$ac_cv_func_SSL_library_init" = xyes; then :
and replace them with
if test xyes = xyes; then :

Roger

[zykh]

not commenting on the issue, but workaround for workaround: why not enabling caching (./configure ... -C) and override the cached value of the ac_cv_func_SSL_library_init var?

[Luo2Jie2]

I never use the configure cache - I always recalculate everything everytime. Perhaps a bad habit, but I was once caught out by stuff hanging around in the cache. Roger

[Luo2Jie2]

It looks as if this is a duplicate of issue "openssl 1.1 support #429", April 2017,
#429 and covered by
"Add support for openssl-1.1.0 #504", Nov 2017,
#504

Roger