Update ci.yml

Author: mcbarton

.github/workflows/ci.yml

@@ -292,7 +292,7 @@ jobs:
           echo "CXX=g++-${vers}" >> $GITHUB_ENV
         else
           echo "SDKROOT=$(xcrun --sdk macosx --show-sdk-path)" >> $GITHUB_ENV
-          if [[ "$ARCHITECHURE" != "x86_64" ]]; then
+          if [[ "$ARCHITECHURE" == "arm64" ]]; then
             echo "CC=$(brew --prefix llvm@18)/bin/clang" >> $GITHUB_ENV
             echo "CXX=$(brew --prefix llvm@18)/bin/clang++" >> $GITHUB_ENV
           else
@@ -764,7 +764,7 @@ jobs:
           echo "CXX=g++-${vers}" >> $GITHUB_ENV
         else
           echo "SDKROOT=$(xcrun --sdk macosx --show-sdk-path)" >> $GITHUB_ENV
-          if [[ "$ARCHITECHURE" != "x86_64" ]]; then
+          if [[ "$ARCHITECHURE" == "arm64" ]]; then
             echo "CC=$(brew --prefix llvm@18)/bin/clang" >> $GITHUB_ENV
             echo "CXX=$(brew --prefix llvm@18)/bin/clang++" >> $GITHUB_ENV
           else