diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index a1449821c..f817358ac 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -7,7 +7,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [macOS-11, ubuntu-24.04]
+        os: [macos-12, ubuntu-24.04]
 
     env:
       PREFIX: install
diff --git a/install.sh b/install.sh
index f96b414b4..0fc02061a 100755
--- a/install.sh
+++ b/install.sh
@@ -20,7 +20,7 @@ yes | ./install.sh
 EOF
 }
 
-GCC_VERSION=14
+GCC_VERSION=${GCC_VERSION:=14}
 GASNET_VERSION="stable"
 
 list_prerequisites()