Do not use objcopy on macOS

On macOS, it is not used to localize symbols in dynamic libraries
(libruby.dylib and libyjit.o).  Instead, using `objcopy` which does
not support recent mach-O causes linker errors as bellow.

```
linking shared-library libruby.3.3.dylib
error: cannot parse the debug map for 'libruby.3.3.dylib': Invalid data was encountered while parsing the file
linking ruby
ld: malformed mach-o: LC_*_DYLIB load command string extends beyond end of load command file './libruby.3.3.dylib'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
```

Author: nobu

configure.ac

@@ -235,7 +235,7 @@ AS_CASE(["${build_os}"],
     AC_PATH_TOOL([NM], [nm], [/usr/ccs/bin/nm], [/usr/ccs/bin:$PATH])
 ])
 AS_CASE(["${target_os}"],
-[cygwin*|msys*|mingw*], [
+[cygwin*|msys*|mingw*|darwin*], [
     ac_cv_prog_ac_ct_OBJCOPY=":"
 ])
 
@@ -507,15 +507,6 @@ AS_CASE(["$target_os"],
 [hiuxmpp*], [AC_DEFINE(__HIUX_MPP__)])    # by TOYODA Eizi <toyoda@npd.kishou.go.jp>
 
 
-AS_IF([test "$OBJCOPY" != :], [
-    AC_MSG_CHECKING([if $OBJCOPY works to localize symbols])
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[void conftest_objcopy(void) {}]])],
-    [
-        $OBJCOPY -w -L '*conftest_*' conftest.$OBJEXT 2>/dev/null || OBJCOPY=:
-    ])
-    AS_IF([test "$OBJCOPY" = :], [AC_MSG_RESULT(no)], [AC_MSG_RESULT(yes)])
-])
-
 AC_PROG_LN_S
 AC_PROG_MAKE_SET
 AC_PROG_INSTALL