tox.ini [homebrew-llvm]: Set CC, CXX to full path

Author: Matthias Koeppe

tox.ini

@@ -449,6 +449,8 @@ setenv =
     gcc_11:                   CONFIG_CONFIGURE_ARGS_2=--with-system-gcc=force CC=gcc-11 CXX=g++-11 FC=gfortran-11
     llvm:                     CONFIG_CONFIGURE_ARGS_2=--with-system-gcc=force CC=clang CXX=clang++
     llvm:                       EXTRA_SAGE_PACKAGES_2=llvm
+    # LLVM is keg-only
+    homebrew-llvm:            CONFIG_CONFIGURE_ARGS_2=--with-system-gcc=force CC={env:HOMEBREW}/opt/llvm/bin/clang CXX={env:HOMEBREW}/opt/llvm/bin/clang++
     macos-nohomebrew:         CONFIG_CONFIGURE_ARGS_2=--with-system-gcc=force CC="$CONFIGURED_CC" CXX="$CONFIGURED_CXX" --with-mp=gmp --without-system-mpfr --without-system-readline --without-system-boost --without-system-boost_cropped
     macos-nohomebrew:           CONFIGURED_CXX=g++ -isysroot {env:MACOS_SDK}
     macos-nohomebrew:           CONFIGURED_CC=gcc -isysroot {env:MACOS_SDK}