enable universal2 wheels

Author: jswhit

.github/workflows/build-wheels.yml

@@ -31,6 +31,13 @@ jobs:
             platform: x32
           - os: macos-latest
             platform: aarch64
+        include:
+          - python-version: "3.9"
+            os: macos-10.15
+            platform: x86_64
+          - python-version: "3.10"
+            os: macos-10.15
+            platform: x86_64
     env:
       BUILD_COMMIT: v1.5.1.1rel
       MB_ML_VER: 2014
@@ -78,6 +85,8 @@ jobs:
         if [ "macos-latest" == "${{ matrix.os }}" ]; then echo "TRAVIS_OS_NAME=osx" >> $GITHUB_ENV; else echo "TRAVIS_OS_NAME=${{ matrix.os }}" >> $GITHUB_ENV; fi
         if [ "schedule" == "${{ github.event_name }}" ]; then echo "TRAVIS_EVENT_TYPE=cron" >> $GITHUB_ENV; else echo "TRAVIS_EVENT_TYPE=${{ github.event_name }}" >> $GITHUB_ENV; fi
         if [ "schedule" == "${{ github.event_name }}" ]; then echo "BUILD_COMMIT=master" >> $GITHUB_ENV; else echo "BUILD_COMMIT=$BUILD_COMMIT" >> $GITHUB_ENV; fi
+        # make universal2 wheels on macos 10.15 by cross-compiling
+        if [ "macos-10.15" == "${{ matrix.os }}" ]; then echo "PLAT=universal2" >> $GITHUB_ENV; fi
     - name: Setup Special Environment variables for aarch64
       if: startsWith(matrix.platform,'aarch64')
       run: |

.gitmodules

@@ -1,6 +1,6 @@
 [submodule "multibuild"]
 	path = multibuild
-	url = https://github.com/matthew-brett/multibuild
+	url = https://github.com/multi-build/multibuild
 [submodule "cftime"]
 	path = cftime
 	url = https://github.com/Unidata/cftime