The code assumed that if __SSE2__ is defined, then 64-bit
integer types are available. This is not the case apparently
for certain multilib compiler targets like x86_32.x86 used
by Gentoo.
This patch fixes the issue by disabling the special code
path when 64-bit integer types are not available.
https://gitlab.freedesktop.org/freetype/freetype/-/issues/1071