on macosx set /usr/bin/gcc as linker in default StdEnv environment

Pm/PmEnvironment.icl

@@ -196,7 +196,7 @@ t_StdEnv20
 	, target_stat	= Nil
 	, target_comp	= compiler_and_linker_directory+++DirSeparatorString+++IF_WINDOWS "CleanCompiler.exe" "cocl"
 	, target_cgen	= compiler_and_linker_directory+++DirSeparatorString+++IF_WINDOWS "CodeGenerator.exe" "cg"
-	, target_link	= compiler_and_linker_directory+++DirSeparatorString+++IF_WINDOWS "StaticLinker.exe" "linker"
+	, target_link	= IF_MACOSX "/usr/bin/gcc" (compiler_and_linker_directory+++DirSeparatorString+++IF_WINDOWS "StaticLinker.exe" "linker")
 	, target_dynl	= "Tools"+++DirSeparatorString+++"Dynamics"+++DirSeparatorString+++"DynamicLinker.exe"
 	, target_vers	= 920
 	, env_64_bit_processor = IF_INT_64_OR_32 True False
@@ -217,7 +217,6 @@ t_StdIO20 =
 		)
 	}
 
-
 //--
 
 fixAppPaths stup target=:{target_path = path, target_libs = libs, target_objs=objs, target_stat=stat}