Build on all supported platforms

[hadess]

No description provided.

[flathubbot]

Started test build 155021

[flathubbot]

Build 155021 failed

[hadess]

The latest tip for BlastEm still has this in the Makefile:

ifeq ($(CPU),x86_64)
CFLAGS+=-DX86_64 -m64
LDFLAGS+=-m64
else
ifeq ($(CPU),i686)
CFLAGS+=-DX86_32 -m32
LDFLAGS+=-m32
else
$(error $(CPU) is not a supported architecture)
endif
endif

So upstream work should be done to fix this before we can build on all the Flathub supported platforms.