egl/main: convert thread management to use c11 threads

Convert the code to use the C11 threads implementation, and nuke the
Windows non-pthreads code-path. The c11/threads_win32.h abstraction
should be better than the current code.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
1 file changed