[testsuite, Darwin] Fix failing darwin-version-1.c.

Recent platform linkers will no longer accept linking for a target
OS version less than 10.4.  Recent SDKs no longer have the libgcc_s
shims used for 10.4 and 10.5.  So we need to adjust tests that expect
these.

gcc/testsuite/ChangeLog:

2020-01-05  Iain Sandoe  <iain@sandoe.co.uk>

	* gcc.dg/darwin-version-1.c: Adjust test to use different
	options for Darwin4-9 and Darwin10+.

From-SVN: r279888

gcc/testsuite/ChangeLog

+2020-01-05  Iain Sandoe  <iain@sandoe.co.uk>
+
+	* gcc.dg/darwin-version-1.c: Adjust test to use different
+	options for Darwin4-9 and Darwin10+.
+
 2020-01-05  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/93141

gcc/testsuite/gcc.dg/darwin-version-1.c

 /* Basic test of the -mmacosx-version-min option.  */
 
-/* { dg-options "-mmacosx-version-min=10.1" } */
+/* Darwin4 corresponds to MacOS 10.0.  */
+/* { dg-options "-mmacosx-version-min=10.1" { target *-*-darwin[456789]* } } */
+/* Later Darwin linkers decline to link for less than Darwin8/MacOS 10.4.
+   However, we need to make the link for 10.6 because the relevant libgcc_s
+   shim files for 10.4 and 10.5 are also not installed in later SDKs.  */
+/* { dg-options "-mmacosx-version-min=10.6" { target *-*-darwin[123]* } } */
 /* { dg-do link { target *-*-darwin* } } */
 
 int main()
 {
   return 0;
 }
-