Both BII and SS for macOS couldn't be built.
Make sure you can build and run on macOS.

BII build with xcodebuild works for me? If you're using "uae_cpu_2021" yeah I need to revise my patch for that. I'll look in to it.

BII build with xcodebuild works for me?

Yes, as follows.

$ cd BasiliskII/src/MacOSX
$ xcodebuild build -project BasiliskII.xcodeproj -configuration Release

$ cd SheepShaver/src/MacOSX
$ xcodebuild build -project SheepShaver_Xcode8.xcodeproj -configuration Release

If you're using "uae_cpu_2021" yeah I need to revise my patch for that.

uae_cpu_2021 is for Apple Silicon Mac.
In that environment, fpu_ieee is inaccurate because sizeof long double is 8.
uae_cpu_2021 has fpu_mpfr using GMP/MPFR and resolves the issue.

BTW, uae_cpu_2021 has problems with JIT, so x86_64 build uses uae_cpu.

Okay I managed to get a universal binary built on intel, the trick is to build gmp/mpfr with CFLAGS="-arch arm64" CXXFLAGS="$CFLAGS" ./configure -host=aarch64-apple-darwin --disable-shared but I do not have an ARM mac to test it on.

SheepShaver seemed to be failing because SDL1 was removed. I fixed that, however the build still fails for me because it can't find GTK+? I have it installed via brew.

SheepShaver seemed to be failing because SDL1 was removed. I fixed that, however the build still fails for me because it can't find GTK+? I have it installed via brew.

GTK+ is not used when building with xcodebuild.
SS of your latest source can be built but crashes.

I do not have an ARM mac to test it on.

If you can't debug with Apple Silicon, I can't merge this PR.
Can you modify your PR so that it doesn't affect Mac Platform?

Okay turns out my SheepShaver build was being messed up by having a lingering Unix/config.h from a unix build. I deleted it and I have a working SheepShaver build here.

Anyone else out there with apple silicon want to help out with this?

I now have a borrowed Apple Silicon machine, and I am happy to help out. On my Intel Mac, under Big Sur, I tried to build gmp with the configure command shown above:

CFLAGS="-arch arm64" CXXFLAGS="$CFLAGS" ./configure -host=aarch64-apple-darwin --disable-shared

and got no error messages from configure or make. But make check showed this failure:

/Applications/Xcode.app/Contents/Developer/usr/bin/make  check-TESTS
FAIL: t-bswap
FAIL: t-constants
FAIL: t-count_zeros
FAIL: t-hightomask
FAIL: t-modlinv
FAIL: t-popc
FAIL: t-parity
FAIL: t-sub

Am I doing something wrong? Is it possible that something I installed with brew is causing the problem? This is the list of my brew installs:

edward@MacBook-Pro-Big-Sur gmp-6.2.1 % brew list
==> Formulae
boost		glib		libodfgen	libwps		pcre		writerperfect
doxygen		icu4c		librevenge	libxml2		python@3.9	xz
gdbm		libffi		libwpd		mpdecimal	readline
gettext		libgsf		libwpg		openssl@1.1	sqlite

Again, I'll be glad to test this on Apple Silicon, but obviously I need to sort out this gmp problem first.

You built arm64 binaries, so make check should fail on Intel.
If you want to check GMP/MPFR, build them on Apple Silicon.

Thank you for that explanation. I've now followed the instructions and built a universal Basilisk II on an Intel Mac by building both GMP and MPFR with the ./configure command shown here, followed by make and sudo make install and then building with: xcodebuild build -project BasiliskII.xcodeproj -configuration Release. The resulting executable runs on Apple Silicon. Thank you!

May I suggest that the instructions on the main page should be clarified slightly? Instead of On an Intel Mac, change the configure command as follows: maybe say something like On an Intel Mac, change the configure command for both GMP and MPFR as follows, and ignore the make check command:

Also, should the instructions say to edit the schemes of the two use_cpu schemes to change Debug to Release? I've been doing this, but I don't know if it's useful

Thank you again for all your work on this project!

Also, should the instructions say to edit the schemes of the two use_cpu schemes to change Debug to Release? I've been doing this, but I don't know if it's useful

The subproject configuration is same as the main project regardless of individual settings, so there is no need to set it.

I changed README.md description to build with xcodebuild for clarity.

I was also able to build with the full Xcode, but I didn't check the resulting build on an Apple Silicon Mac. If I do, I'll report back. Thank you again.

I now have a borrowed Apple Silicon machine, and I am happy to help out. On my Intel Mac, under Big Sur, I tried to build gmp with the configure command shown above:

CFLAGS="-arch arm64" CXXFLAGS="$CFLAGS" ./configure -host=aarch64-apple-darwin --disable-shared

and got no error messages from configure or make. But make check showed this failure:

/Applications/Xcode.app/Contents/Developer/usr/bin/make  check-TESTS
FAIL: t-bswap
FAIL: t-constants
FAIL: t-count_zeros
FAIL: t-hightomask
FAIL: t-modlinv
FAIL: t-popc
FAIL: t-parity
FAIL: t-sub

Am I doing something wrong? Is it possible that something I installed with brew is causing the problem? This is the list of my brew installs:

edward@MacBook-Pro-Big-Sur gmp-6.2.1 % brew list
==> Formulae
boost		glib		libodfgen	libwps		pcre		writerperfect
doxygen		icu4c		librevenge	libxml2		python@3.9	xz
gdbm		libffi		libwpd		mpdecimal	readline
gettext		libgsf		libwpg		openssl@1.1	sqlite

Again, I'll be glad to test this on Apple Silicon, but obviously I need to sort out this gmp problem first.

I have M1, and have the same problem when build gmp on it :)

============================================================================
Testsuite summary for GNU MP 6.2.1
============================================================================
# TOTAL: 50
# PASS:  17
# SKIP:  0
# XFAIL: 0
# FAIL:  33
# XPASS: 0
# ERROR: 0

Try uname -m in the terminal where you built GMP.
If the result is not arm64, turn Rosetta off and start over.

Closing this, I have a new release in the works with significant patch reworking which obsoletes all this.