ld sysroot-prefix test fails

* testsuite/ld-scripts/sysroot-prefix.exp: Exclude some targets.

ld/ChangeLog

@@ -1,3 +1,7 @@
+2021-01-05  Alan Modra  <amodra@gmail.com>
+
+	* testsuite/ld-scripts/sysroot-prefix.exp: Exclude some targets.
+
 2021-01-05  Alan Modra  <amodra@gmail.com>
 
 	PR ld/26256

ld/testsuite/ld-scripts/sysroot-prefix.exp

@@ -17,6 +17,15 @@
 # Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
 # MA 02110-1301, USA.
 
+# Don't run on alpha-vms which requires linking with other libraries,
+# or on targets that complain about relocations in read-only sections.
+if { [istarget *-*-vms]
+     || [istarget bfin-*-*]
+     || [istarget frv-*-*]
+     || [istarget lm32-*-*] } then {
+    return
+}
+
 # Check that scripts using the "=" sysroot-prefix work, for both
 # toolchains with and without --sysroot support.