Fix typo in build-script-impl

targetting -> targeting

Author: Ikko Ashimine

utils/build-script-impl

@@ -2497,7 +2497,7 @@ for host in "${ALL_HOSTS[@]}"; do
 
         # When we are building LLVM copy over the compiler-rt
         # builtins for iOS/tvOS/watchOS to ensure that Swift's
-        # stdlib can use compiler-rt builtins when targetting iOS/tvOS/watchOS.
+        # stdlib can use compiler-rt builtins when targeting iOS/tvOS/watchOS.
         if [[ "${product}" = "llvm" ]] && [[ "${BUILD_LLVM}" = "1" ]] && [[ "$(uname -s)" = "Darwin" ]]; then
             copy_embedded_compiler_rt_builtins_from_darwin_host_toolchain "$(build_directory_bin ${host} llvm)/.."
         fi