ci: still build zig even though we are using (older) zig cc

CMakeLists.txt

@@ -467,7 +467,7 @@ set(BUILD_ZIG1_ARGS
     --pkg-end
 )
 
-if("${ZIG_TARGET_TRIPLE}" STREQUAL "native")
+if("${ZIG_EXECUTABLE}" STREQUAL "")
   add_custom_target(zig_build_zig1 ALL
       COMMAND zig0 ${BUILD_ZIG1_ARGS}
       DEPENDS zig0

ci/azure/macos_script

@@ -37,7 +37,6 @@ cmake .. \
   -DCMAKE_BUILD_TYPE=Release \
   -DZIG_TARGET_TRIPLE="$ARCH-native-gnu" \
   -DZIG_TARGET_MCPU="baseline" \
-  -DZIG_EXECUTABLE="$ZIG" \
   -DZIG_STATIC=ON
 
 # Now cmake will use zig as the C/C++ compiler. We reset the environment variables