>Cross-compiling Nettle (at least with GNU/Linux as the build system) >is fairly well tested. If you do something like [...]
So if you instead do ./configure --host=aarch64-unknown-linux-gnu --build=powerpc64-unknown-linux-gnu-gcc (cross-compiling, with GNU/Linux as the build system, as you say) then what would you expect EXEEXT and EXEEXT_FOR_BUILD to be, and how would you expect the Makefile to know when to use CC_FOR_BUILD? That's what I can't quite wrap my head around... If it was me I would probably have written COMPILE_FOR_BUILD = $(CC_FOR_BUILD) $< -lm -o $@ and then put $(COMPILE_FOR_BUILD) as the action for any target producing a build-time executable, rather than messing with pattern rules.
