Try to get gmp working on macOS

.github/workflows/linux_newer_py.yml

@@ -16,6 +16,7 @@ jobs:
       - name: Build wheels
         uses: pypa/cibuildwheel@v2.19.2
         env:
+          CIBW_PRERELEASE_PYTHONS: True
           CIBW_BUILD: cp311-manylinux_x86_64 cp312-manylinux_x86_64 cp313-manylinux_x86_64
           CIBW_BEFORE_ALL_LINUX: >
             yum install -y gmp-devel zlib-devel bzip2-devel &&

.github/workflows/macos_newer_py.yml

@@ -16,15 +16,12 @@ jobs:
       - name: Build wheels
         uses: pypa/cibuildwheel@v2.19.2
         env:
+          CIBW_PRERELEASE_PYTHONS: True
           CIBW_BUILD: cp311-* cp312-* cp313-*
-          # gmp already installed on macos runner
           CIBW_BEFORE_ALL_MACOS: >
             python -m pip install wheel setuptools &&
             python setup.py package_assemble &&
-            ln -s /opt/homebrew/opt/gmp/include/gmp.h extinclude &&
-            ln -s /opt/homebrew/opt/gmp/include/gmpxx.h extinclude &&
-            ln -s /opt/homebrew/opt/gmp/lib/libgmp.a extlib &&
-            ln -s /opt/homebrew/opt/gmp/lib/libgmpxx.a extlib
+            bash build_gmp.sh
           CIBW_TEST_COMMAND: python -m regina.test
 
       - uses: actions/upload-artifact@v4

.github/workflows/macos_older_py.yml

@@ -17,15 +17,10 @@ jobs:
         uses: pypa/cibuildwheel@v2.19.2
         env:
           CIBW_BUILD: cp38-* cp39-* cp310-*
-          # gmp already installed on macos runner
           CIBW_BEFORE_ALL_MACOS: >
             python -m pip install wheel setuptools &&
             python setup.py package_assemble &&
-            brew install gmp &&
-            ln -s /opt/homebrew/opt/gmp/include/gmp.h extinclude &&
-            ln -s /opt/homebrew/opt/gmp/include/gmpxx.h extinclude &&
-            ln -s /opt/homebrew/opt/gmp/lib/libgmp.a extlib &&
-            ln -s /opt/homebrew/opt/gmp/lib/libgmpxx.a extlib
+            bash build_gmp.sh
           CIBW_TEST_COMMAND: python -m regina.test
 
       - uses: actions/upload-artifact@v4

.gitignore

@@ -0,0 +1,11 @@
+extlib/libgmp*
+extlib/pkgconfig
+extinclude/gmp*.h
+gmp-*tar.bz2
+gmp_src/
+PKG-INFO
+build/
+dist/
+libxml2-2.9.3/
+regina_*/
+tokyocabinet-1.4.48/

build_gmp.sh

@@ -0,0 +1,52 @@
+#! /bin/bash
+
+set -e
+
+GMPURL=https://ftp.gnu.org/gnu/gmp/
+GMPVERSION=gmp-6.3.0
+
+if [ ! $(uname) = "Darwin" ] ; then
+    echo "This script configured for macOS only"
+    exit 1
+fi
+
+if [[ $(pwd) =~ " " ]]; then
+    echo "Fatal Error: Sorry, the path:"
+    echo "             $(pwd)"
+    echo "             has a space in it, preventing GMP from building"
+    echo "             because of a limitation of libtool."
+    exit 1
+fi
+
+echo Building gmp ...
+
+
+if [ ! -e ${GMPVERSION}.tar.bz2 ] ; then
+    echo "Downloading GMP source archive ..." ;
+    curl -O ${GMPURL}${GMPVERSION}.tar.bz2 ;
+fi
+if [ ! -e gmp_src ] ; then
+    echo "Extracting gmp source code ..."
+    tar xjf ${GMPVERSION}.tar.bz2
+    mv ${GMPVERSION} gmp_src
+fi
+cd gmp_src
+export ABI=64
+if /usr/bin/machine | grep arm > /dev/null ; then
+    BUILD_SYSTEM=arm64-none-darwin
+    export CFLAGS="-mmacosx-version-min=11.0"    
+else
+    BUILD_SYSTEM=x86_64-none-darwin
+    export CFLAGS="-mmacosx-version-min=10.9 -mno-avx2 -mno-bmi2"
+fi
+echo $BUILD_SYSTEM
+# Use the old linker for x86_64 to avoid a spurious "branch8 out of range" error.
+if [ `/usr/bin/ld -ld_classic 2> >(grep -c warning)` != "0" ] ; then
+    export LDFLAGS="-ld_classic"
+fi
+
+
+./configure --enable-cxx --with-pic --build=${BUILD_SYSTEM} --prefix=$(pwd)/local
+make install
+ln -s local/lib/* ../extlib
+ln -s local/include/* ../extinclude