Enums may be represented with a smaller type than int; however, they are
automatically promoted to int when passed in va_arg lists, just as
short, char, etc. are. GCC thus "knows" that you never want to call
va_arg with an enum type, and instead inserts an abort.
Mostly this is adding appropriate #includes and declarations,
but for WmImage.c we also change from using the proper name
for XmeGetMask, rather than the identical but renamed
version _DtGetMask which is not exported in any header.