Linux-PGI: Prevent -rdynamic ending up in flags
Ensure that PGI on Linux keeps its
CMAKE_SHARED_LIBRARY_LINK_<LANG>_FLAGS empty, especially of
In CMakeFortranInformation a lot of flags will be copied from their C equivalents if they're not defined. By using a combination of GCC and PGFortran, this will lead to
-rdynamic ending up in the PGI flags and none of the PGI compilers understand that flag, crashing with a fatal error.