workflows/release-binaries: Disable Flang on x86_64 macOS (llvm#127216)

The flang build was taking 2-3 hours and causing the entire job to
timeout, so we need to disable it.

Author: tstellar

.github/workflows/release-binaries.yml

@@ -138,6 +138,11 @@ jobs:
             arches=arm64
           else
             arches=x86_64
+            # Disable Flang builds on macOS x86_64.  The FortranLower library takes
+            # 2-3 hours to build on macOS, much slower than on Linux.
+            # The long build time causes the release build to time out on x86_64,
+            # so we need to disable flang there.
+            target_cmake_flags="$target_cmake_flags -DLLVM_RELEASE_ENABLE_PROJECTS='clang;lld;lldb;clang-tools-extra;bolt;polly;mlir'"
           fi
           target_cmake_flags="$target_cmake_flags -DBOOTSTRAP_BOOTSTRAP_DARWIN_osx_ARCHS=$arches -DBOOTSTRAP_BOOTSTRAP_DARWIN_osx_BUILTIN_ARCHS=$arches"
         fi