libtommath 1.2.0 c403b66082
("hcrypto: import libtommath v1.2.0") needs more from stdint.h
than what Heimdal previously declared. Add more integer type
declarations and integer MIN/MAX macros.
Also, on Windows declare 64-bit integers using __int64 as
"long long" is not supported as 64-bit type across all visual
studio compiler versions.
Change-Id: I944bedc67bcb26374ffb30eb3dfd7c6108a98fc3