CMakeLists.txt points at missing file

[JayFoxRox]

https://github.com/XboxDev/nxdk-pdclib/commit/18e3b16e3bf5d73dbfe842c95c5bb6b0ee100a01 introduced a bug which breaks CMake (which was added later in 4246158ac7f7fbca78bf152843eda5e051d36dc5); this prevents running tests on non-Xbox platforms.

$ mkdir build
$ cd build
$ cmake ..
++ CMAKE_BUILD_TYPE not set. Defaulting to 'Debug'.
-- Configuring done
CMake Error at CMakeLists.txt:309 (add_library):
  Cannot find source file:

    functions/_PDCLIB/assert.c

  Tried extensions .c .C .c++ .cc .cpp .cxx .cu .m .M .mm .h .hh .h++ .hm
  .hpp .hxx .in .txx

[...]

I'm not sure how to resolve this most gracefully.

Generally it feels like https://github.com/XboxDev/nxdk-pdclib/commit/18e3b16e3bf5d73dbfe842c95c5bb6b0ee100a01 shouldn't require changes to existing pdclib code. We have extension hooks now and there has always been the optimization overlay (which works as long as we don't use wildcards in our Makefiles).