Remove -fvisibility=hidden build param

Using this causes the compiler to convert *all* global symbols to
local symbols, which is *absolutely* not the correct thing to do.

This was causing the build-time test suite to immediately fail,
because the symbols (e.g. sk_api_version) inside the test sk-dummy.so
were being built as local symbols instead of global symbols, which
broke the dlsym() call to load the sk_api_version() symbol.

SPECS/openssh/openssh.spec

@@ -130,8 +130,7 @@ popd
 %patch319 -p1 -b .cve-2023-48795-0009
 
 %build
-# The -fvisibility=hidden is needed for clean build of the pam_ssh_agent_auth.
-export CFLAGS="$CFLAGS -fvisibility=hidden -fpic"
+export CFLAGS="$CFLAGS -fpic"
 SAVE_LDFLAGS="$LDFLAGS"
 export LDFLAGS="$LDFLAGS -pie -z relro -z now"
 %configure \