I stumbled into a bug on line 368 in src/opentest/serializer.cpp where int64_t was used but not defined. Changing it to LargestInt worked, but I wonder why there's no support for long long in linux.
There is a __GLIBC_HAVE_LONG_LONG define (features.h) to check for long long support and there are also 64 bit defines in stdint.h.
Thanks for reporting this. Though it should already have been fixed in CVS (I caught it with mingw).
stdint.h will probably be the way to go for compiler that provides this C99 header. Though, we'll need to come up with other way for older compiler (e.g. gcc 2.8.5 & msvc <= 7.1) which I think to not provide it.