Define ARCHITECHURE=$(uname -m) to pick compiler correctly on osx15 (ci)

Author: mcbarton

.github/workflows/ci.yml

@@ -292,6 +292,7 @@ jobs:
           echo "CXX=g++-${vers}" >> $GITHUB_ENV
         else
           echo "SDKROOT=$(xcrun --sdk macosx --show-sdk-path)" >> $GITHUB_ENV
+          export ARCHITECHURE=$(uname -m)
           if [[ "$ARCHITECHURE" == "arm64" ]]; then
             echo "CC=$(brew --prefix llvm@18)/bin/clang" >> $GITHUB_ENV
             echo "CXX=$(brew --prefix llvm@18)/bin/clang++" >> $GITHUB_ENV
@@ -764,6 +765,7 @@ jobs:
           echo "CXX=g++-${vers}" >> $GITHUB_ENV
         else
           echo "SDKROOT=$(xcrun --sdk macosx --show-sdk-path)" >> $GITHUB_ENV
+          export ARCHITECHURE=$(uname -m)
           if [[ "$ARCHITECHURE" == "arm64" ]]; then
             echo "CC=$(brew --prefix llvm@18)/bin/clang" >> $GITHUB_ENV
             echo "CXX=$(brew --prefix llvm@18)/bin/clang++" >> $GITHUB_ENV