[committed][gdb/testsuite] Fix gdb_unbuffer_output return-type

[Tom de Vries <tdevries@suse.de>]

Hi,

When running test-case gdb.base/shlib-call.exp with clang, we get:
...
gdb compile failed, In file included from shmain.c:6:
unbuffer_output.c:39:1: warning:
      control reaches end of non-void function [-Wreturn-type]
}
^
1 warning generated.
...

Fix this by changing the return-type to void.

Tested on x86_64-linux.

Committed to trunk.

Thanks,
- Tom

[gdb/testsuite] Fix gdb_unbuffer_output return-type

gdb/testsuite/ChangeLog:

2020-05-06  Tom de Vries  <tdevries@suse.de>

	* lib/unbuffer_output.c (gdb_unbuffer_output): Change return type to
	void.

---
 gdb/testsuite/lib/unbuffer_output.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gdb/testsuite/lib/unbuffer_output.c b/gdb/testsuite/lib/unbuffer_output.c
index d272f5e3a9c..afb6f4188b4 100644
--- a/gdb/testsuite/lib/unbuffer_output.c
+++ b/gdb/testsuite/lib/unbuffer_output.c
@@ -22,7 +22,7 @@
 #include <unistd.h>
 #endif
 
-static int
+static void
 gdb_unbuffer_output (void)
 {
   /* Always force this for Windows testing.  To a native Windows