Update ci.yml

Author: mcbarton

.github/workflows/ci.yml

@@ -299,7 +299,8 @@ jobs:
                 brew install llvm@15
                 brew remove llvm@18
                 brew cleanup
-                sudo xcode-select -s /Applications/Xcode_15.4.app
+                export LDFLAGS="-L/opt/homebrew/opt/llvm@15/lib"
+                export CPPFLAGS="-I/opt/homebrew/opt/llvm@15/include"
                 echo "CC=$(brew --prefix llvm@15)/bin/clang" >> $GITHUB_ENV
                 echo "CXX=$(brew --prefix llvm@15)/bin/clang++" >> $GITHUB_ENV
             else
@@ -782,7 +783,8 @@ jobs:
                 brew install llvm@15
                 brew remove llvm@18
                 brew cleanup
-                sudo xcode-select -s /Applications/Xcode_15.4.app
+                export LDFLAGS="-L/opt/homebrew/opt/llvm@15/lib"
+                export CPPFLAGS="-I/opt/homebrew/opt/llvm@15/include"
                 echo "CC=$(brew --prefix llvm@15)/bin/clang" >> $GITHUB_ENV
                 echo "CXX=$(brew --prefix llvm@15)/bin/clang++" >> $GITHUB_ENV
             else