cmake: Compiler language support checks.
cmake: Compiler language support checks.

Added "checked" usage for:

 * -pedantic
 * -Wall

And -std=gnu0x, we currently rely on this... which is a shame
since it is not well supported amongst compilers.

Added -std=c99 for C code, we did not specify a standard prior to this change.

madsbk/bohrium,bh107/bohrium,madsbk/bohrium,madsbk/bohrium,bh107/bohrium,madsbk/bohrium,bh107/bohrium,bh107/bohrium