[committed][gdb/testsuite] Fix gnatmake_version_at_least

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

Hi,

After de-installing gnatmake, I get:
...
Running src/gdb/testsuite/gdb.ada/rename_subscript_param.exp ...
ERROR: tcl error sourcing src/gdb/testsuite/gdb.ada/rename_subscript_param.exp.
ERROR: couldn't execute "gnatmake": no such file or directory
    while executing
"exec $gnatmake --version"
    (procedure "gnatmake_version_at_least" line 4)
...

Fix this by wrapping the exec call in a catch call.

Tested with and withouth gnatmake installed on x86_64-linux.

Committed to trunk.

Thanks,
- Tom

[gdb/testsuite] Fix gnatmake_version_at_least

gdb/testsuite/ChangeLog:

2020-02-13  Tom de Vries  <tdevries@suse.de>

	* lib/ada.exp (gnatmake_version_at_least): Wrap exec call in a catch
	call.

---
 gdb/testsuite/lib/ada.exp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/gdb/testsuite/lib/ada.exp b/gdb/testsuite/lib/ada.exp
index f8a6a723bb..726977d98f 100644
--- a/gdb/testsuite/lib/ada.exp
+++ b/gdb/testsuite/lib/ada.exp
@@ -136,7 +136,9 @@ proc find_ada_tool {tool} {
 proc gnatmake_version_at_least { major } {
     set gnatmake [gdb_find_gnatmake]
     set gnatmake [lindex [split $gnatmake] 0]
-    set output [exec $gnatmake --version]
+    if {[catch {exec $gnatmake --version} output]} {
+	return 0
+    }
     if { [regexp {GNATMAKE ([^ .]+).([^ .]+).([^ .]+)} $output \
 	      match gnatmake_major gnatmake_minor gnatmake_micro] } {
 	if { $gnatmake_major >= $major } {