Since we rely on the dynamic linker to find the library for us via
dlopen(), we need to have DL_OPENGL be .so.N, not the full library
filename, as ldconfig doesn't cache the full filename
Use of TARGET_SONAME_FILE requires the library to be marked as SHARED,
not MODULE
This closes pull request #370
On mac and windows, the libraries are always meant to be portable,
therefore the naming convention does not need to change for each
revision. For linux this makes sense; windows and mac not so much.
Because libobs-opengl is a public library, it's customary to have SONAME
embedded in the library file. Also remove the prefix override and
remove the prefixing "lib" from the output name. This also requires us
to pass the library file name to dlopen invocations.
