Use static_assert if supported by the compiler.
Use static_assert if supported by the compiler.

This fixes issue #44: VCD_COMPILE_ASSERT warns with -Wunused-local-typedef

elly/open-vcdiff,Steelskin/open-vcdiff,elly/open-vcdiff,google/open-vcdiff,google/open-vcdiff,elly/open-vcdiff,Steelskin/open-vcdiff,Steelskin/open-vcdiff,google/open-vcdiff