Fix link failure when building on Fedora 64bit

[kicsyromy]

Fix link failure when building on Fedora 64bit

Fedora and other Linux distributions tend to use lib64 as the library directory and when building and installing the native library with CMake the directory structure in the prefix conforms to this standard.

This makes the linking fail since the search directory for libnng is set to lib.

This patch adds lib64 to the library search path on Linux.

The same issue is also present for mbedtls and was fixed there as well.

[DoumanAsh]

Hm, interesting I would assume cmake create would pick up correct search location automatically, but that's not the case then?

[DoumanAsh]

If possible, can you shall full build log(cargo build --verbose) from your machine where you encounter issue?

[kicsyromy]

If possible, can you shall full build log(cargo build --verbose) from your machine where you encounter issue?

build.log

[kicsyromy]

Hm, interesting I would assume cmake create would pick up correct search location automatically, but that's not the case then?

CMake itself, I think, is doing the right thing. The issue is that it is assumed that the build directory contains: bin, include and lib, but, in fact, it contains bin, include, and lib64 on Fedora.

Somehow CMake picks up some environmental setting and creates a lib64 directory instead of lib which in 99% of cases is the right thing to do, but here, because of the previous assumption, leads to a link failure.

Of note that this does not happen on Ubuntu since it uses a different library differentiation technique.

[DoumanAsh]

Hm looking back I forgot that cmake crate just returns root of installation directoy
So it is build script responsibility to find correct folder

I'm thinking instead of doing rename, we should add lib64 to search path maybe?
That would be safe in case something changes and both lib and lib64 would be created

[DoumanAsh]

Thanks, I will merge and release it later after work

[DoumanAsh]

Released 1.9.0-beta.2 (will release nng-c bump a bit later)

[kicsyromy]

Thanks!