Commit 247cee9ff410fe6e91536ff55cfaf5498db96770 added PERL_INT_FAST8_T PERL_UINT_FAST8_T PERL_INT_FAST16_T PERL_UINT_FAST16_T which emulate the respective C99 typedefs on non-C99 compilers. These are marked for core and core extension use only until we are sure this is a good idea. Often, I write a loop whose max value is much less than an int. This allows one to specify the minimum size needed, but telling the compiler to use a larger sized one if it deems that the smaller size creates a performance penalty. Previously, there was added PERL_UINT_MAX_T PERL_INT_MAX_T typedefs that evaluate to the longest type on the platform. This would allow some code that uses #ifdef's about quads to not have to have the #ifdef's.