I was able to build giac 1.2.3.25+dfsg1-3 on arm64 with this "patch":
perl -i -pe 's/^#ifdef __x86_64__$/#if 1/;' src/gen.h perl -i -pe 's/^#ifndef __x86_64__$/#if 0/;' src/first.h Obviously that change would break it on 32-bit architectures. A proper fix might be to use something like ~(uintptr_t)3 in gen.h, avoiding the preprocessor, and in first.h something like: #include <stdint.h> #if UINTPTR_MAX < 0xffffffffffffffff
