Restore Linux and macOS builds

Author: pcolby

.github/workflows/build.yaml

@@ -14,7 +14,6 @@ env:
 
 jobs:
   linux:
-    if: false
     runs-on: ubuntu-${{ matrix.os }}${{ matrix.arch == 'arm64' && '-arm' || '' }}
     strategy:
       fail-fast: false
@@ -220,7 +219,6 @@ jobs:
           if-no-files-found: error
 
   mac:
-    if: false
     runs-on: ${{ matrix.os }}
     env:
       CMAKE_BUILD_PARALLEL_LEVEL: ${{ matrix.os == 'macos-13' && 4 || 3 }}