Allow proper runtime linking with pkgin-installed libraries on NetBSD

[devfonks]

The NetBSD runtime linker appears to look in the same places as the dynamic linker on other systems but does not search LD_LIBRARY_PATH like it does on others, in what appears to be a deliberate design decision. Whatever the case, in order to prevent a pkgin user needing to symlink tons of libraries from the /usr/X11R7 and /usr/pkg trees into /usr/local/lib, Psi should tell the compiler to include parameters for the runtime linker to find the necessary libraries on that system. To aid in portability, I have created some conditions in CMakeLists.txt to allow for setting the CFLAGS/CXXFLAGS variables with the appropriate parameters.

I have done minimal testing on NetBSD-9.1 amd64, and it builds successfully and runs correctly with these flags set (where it would build successfully but fail to link at runtime before). I have not thoroughly tested the program's functionality but it does start and show the UI.

Though it shouldn't matter much, I should note that I only build Psi+ (I haven't used base Psi in quite a few years now). If anyone else wishes to test regular Psi builds your input would be appreciated.

[Ri0n]

Thanks @devfonks.
Unfortunately don't have NetBSD to test. But the PR looks good to me.
Even so I'm a little surprised it's necessary to do such stuff for every single package.

[devfonks]

I am too, but it seems this is a deliberate decision for pkgin, mainly to keep binaries from polluting a custom tree, perhaps? I don't know if pkgsrc does the same thing but this should at least help the user who is wanting to build in that case.

[Ri0n]

as @Vitozz noticed on the chat, there is an interesting variable https://cmake.org/cmake/help/latest/variable/CMAKE_INSTALL_RPATH.html#variable:CMAKE_INSTALL_RPATH seems to be solving the same problem.

[Vitozz]

Yep, much proper way is to use cmake functions. For example:

# Detect NetBSD and handle library path accordingly
STRING (REGEX MATCH "NetBSD" PROJECT_OS_NETBSD ${CMAKE_SYSTEM_NAME})
if(PROJECT_OS_NETBSD)
set( CMAKE_BUILD_WITH_INSTALL_RPATH FALSE )
list(APPEND CMAKE_INSTALL_RPATH
"/usr/X11R7/lib"
"/usr/pkg/lib"
"/usr/pkg/qt5/lib"
)
endif()

this can be added before executable creation in src/CMakeLists.txt
I can't test this code because I don't have NetBSD

[devfonks]

Thanks for pointing that out, I didn't know about that. I will see about testing that fix tomorrow when I have free time. If it works then I will open another PR to revert this change and implement the proper fix.