[PATCH] gdb.base/async.exp: Handle "asynchronous execution not supported"

[Kevin Buettner <kevinb@redhat.com>]

This change eliminates some failures on simulator targets and makes
the test run a bit quicker too - without this change, we have to wait
for timeouts.

gdb/testsuite/ChangeLog:
    
    	* gdb.base/async.exp (proc test_background): Add case
    	for asynchronous execution not supported.
---
 gdb/testsuite/gdb.base/async.exp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/gdb/testsuite/gdb.base/async.exp b/gdb/testsuite/gdb.base/async.exp
index 2d3fb73..8226244 100644
--- a/gdb/testsuite/gdb.base/async.exp
+++ b/gdb/testsuite/gdb.base/async.exp
@@ -61,6 +61,9 @@ proc test_background {command before_prompt after_prompt {message ""}} {
 	-re "$gdb_prompt.*completed\.\r\n" {
 	    fail "$message"
 	}
+	-re ".*Asynchronous execution not supported on this target..*" {
+	    unsupported "Asynchronous execution not supported: $message"
+	}
 	timeout  {
 	    fail "$message (timeout)"
 	}