Unable to disable/redefine MPARAM (`-m64`) for cross-compilation

[plaes]

I'm attempting to cross-compile mame on x86_64 host targeting arm64/aarch64 platform, but unfortunately I cannot find a way to disable the -m64 being passed on to compiler:

$ CROSS_BUILD=1 \
OVERRIDE_CC=aarch64-linux-gnu-gcc \
OVERRIDE_CXX=aarch64-linux-gnu-g++ \
OVERRIDE_LD=aarch64-linux-gnu-ld \
make

...

GCC 8 detected
Precompiling src/emu/emu.h...
aarch64-linux-gnu-g++: error: unrecognized command line option ‘-m64’
aarch64-linux-gnu-g++: error: unrecognized command line option ‘-m64’
make[2]: *** [precompile.make:317: ../../../../linux_gcc/obj/x64/Release/emu.h.gch] Error 1
make[1]: *** [Makefile:94: precompile] Error 2
make: *** [makefile:1379: linux_x64] Error 2

[rb6502]

Cross builds aren't well exercised in the build system, and there's not a great separation in the build system between aarch64 and x64. I ran into this recently when doing the changes necessary to support aarch64 on macOS. That said, it looks like the -m64 comes from the ARCHITECTURE variable on non-Windows systems, so getting rid of -m64 may be as simple as adding ARCHITECTURE=arm64 to your build command line.

[plaes]

Cross builds aren't well exercised in the build system, and there's not a great separation in the build system between aarch64 and x64. I ran into this recently when doing the changes necessary to support aarch64 on macOS. That said, it looks like the -m64 comes from the ARCHITECTURE variable on non-Windows systems, so getting rid of -m64 may be as simple as adding ARCHITECTURE=arm64 to your build command line.

Unfortunately, this did not help. :(

[belegdol]

ARCHITECTURE needs to be blank in order for the -m32/-m64 not to be used. MPARAM is only used for genie so this is not what needs to be adapted, for cross compilation genie still needs to be built for the host architecture.