When calling find_package(wxWidgets ...) allow the first call to fail
because the OpenGL library may not be found. A subsequent call without
listing the OpenGL library is done with REQUIRED.

And if the OpenGL library is not found, skip the OpenGL compile test.

When cross-compiling (e.g. with mxe or other mingw packages) skip the wx
ABI compatibility run tests.

When choosing which minhook lib to link to the wx ABI compat run test
program, check for 64 bit but fallback to 32 bit just in case.