[gdb/testsuite] Add have_startup_shell

Say we disable startup-with-shell, we get:
...
(gdb) run `echo 8`^M
Starting program: a2-run `echo 8`^M
[Thread debugging using libthread_db enabled]^M
Using host libthread_db library "/lib64/libthread_db.so.1".^M
usage:  factorial <number>^M
[Inferior 1 (process 10787) exited with code 01]^M
(gdb) FAIL: gdb.base/a2-run.exp: run "a2-run" with shell (timeout)
...

Fix this by only doing this test if startup-with-shell is supported.

This fixes the test-case on msys2-ucrt64, where startup-with-shell is not
supported.

Likewise in other test-cases.

Tested on x86_64-linux.

6 files changed, 54 insertions, 3 deletions

diff --git a/gdb/testsuite/gdb.base/a2-run.exp b/gdb/testsuite/gdb.base/a2-run.exp
index 4e95e56..966e12a 100644
--- a/gdb/testsuite/gdb.base/a2-run.exp
+++ b/gdb/testsuite/gdb.base/a2-run.exp
@@ -18,6 +18,8 @@
 # Can't do this test without stdio support.
 require {!gdb_skip_stdio_test "a2run.exp"}
 
+set have_startup_shell [have_startup_shell]
+
 #
 # test running programs
 #
@@ -166,9 +168,8 @@ gdb_run_cmd
 setup_xfail "arm-*-coff"
 gdb_test_stdio "" "720" "" "run \"$testfile\" again after setting args"
 
-# GOAL: Test that shell is being used with "run".  For remote debugging
-# targets, there is no guarantee that a "shell" (whatever that is) is used.
-if {![is_remote target]} {
+# GOAL: Test that shell is being used with "run".
+if { $have_startup_shell == 1 } {
     gdb_test_stdio "run `echo 8`" \
 	"40320" "" "run \"$testfile\" with shell"
 }
diff --git a/gdb/testsuite/gdb.base/args.exp b/gdb/testsuite/gdb.base/args.exp
index 33952e4..7b62a75 100644
--- a/gdb/testsuite/gdb.base/args.exp
+++ b/gdb/testsuite/gdb.base/args.exp
@@ -21,6 +21,7 @@ require {!target_info exists noargs}
 # This test requires starting new inferior processes, skip it if the target
 # board is a stub.
 require !use_gdb_stub
+require {expr [have_startup_shell] != -1}
 
 standard_testfile
 
diff --git a/gdb/testsuite/gdb.base/inferior-args.exp b/gdb/testsuite/gdb.base/inferior-args.exp
index 9406c78..dfa1215 100644
--- a/gdb/testsuite/gdb.base/inferior-args.exp
+++ b/gdb/testsuite/gdb.base/inferior-args.exp
@@ -17,6 +17,7 @@
 
 # This does not work on boards that don't support inferior arguments.
 require {!target_info exists noargs}
+require {expr [have_startup_shell] != -1}
 
 standard_testfile .c
 
diff --git a/gdb/testsuite/gdb.base/startup-with-shell.exp b/gdb/testsuite/gdb.base/startup-with-shell.exp
index 80dfdf3..9c016b4 100644
--- a/gdb/testsuite/gdb.base/startup-with-shell.exp
+++ b/gdb/testsuite/gdb.base/startup-with-shell.exp
@@ -22,6 +22,8 @@ require !use_gdb_stub
 # (via dejagnu) yet.
 require {!is_remote target}
 
+require {expr [have_startup_shell] != -1}
+
 standard_testfile
 
 if { [build_executable "failed to prepare" $testfile $srcfile debug] } {
diff --git a/gdb/testsuite/gdb.mi/mi-exec-run.exp b/gdb/testsuite/gdb.mi/mi-exec-run.exp
index a7a61b8..43406cf 100644
--- a/gdb/testsuite/gdb.mi/mi-exec-run.exp
+++ b/gdb/testsuite/gdb.mi/mi-exec-run.exp
@@ -30,6 +30,8 @@ set MIFLAGS "-i=mi"
 # cannot use it, then there is no point in running this testcase.
 require !use_gdb_stub
 
+set have_startup_shell [have_startup_shell]
+
 standard_testfile mi-start.c
 
 if  { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
@@ -172,6 +174,9 @@ remote_exec target "chmod \"a-x\" $binfile.nox"
 foreach_with_prefix inferior-tty {"main" "separate"} {
     foreach_with_prefix mi {"main" "separate"} {
 	foreach_with_prefix force-fail {0 1} {
+	    if { ${force-fail} && $have_startup_shell == -1 } {
+		continue
+	    }
 	    test ${inferior-tty} ${mi} ${force-fail}
 	}
     }
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 041650a..d3e2a45 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -11490,5 +11490,46 @@ gdb_caching_proc have_builtin_trap {} {
     } executable]
 }
 
+# Return 1 if there is a startup shell.  Return -1 if there's no startup shell.
+# Return -1 otherwise.
+
+gdb_caching_proc have_startup_shell {} {
+    if { [is_remote target] } {
+	# For remote debugging targets, there is no guarantee that a "shell"
+	# is used.
+	return -1
+    }
+
+
+    gdb_exit
+    gdb_start
+
+    set re_on \
+	[string_to_regexp "Use of shell to start subprocesses is on."]
+    set re_off \
+	[string_to_regexp "Use of shell to start subprocesses is off."]
+    set re_cmd_unsupported \
+	[string_to_regexp \
+	     {Undefined show command: "startup-with-shell".  Try "help show".}]
+
+    set supported -1
+    gdb_test_multiple "show startup-with-shell" "" {
+	-re -wrap $re_on {
+	    set supported 1
+	}
+	-re -wrap $re_off {
+	    set supported 0
+	}
+	-re -wrap $re_cmd_unsupported {
+	}
+	-re -wrap "" {
+	}
+    }
+
+    gdb_exit
+
+    return $supported
+}
+
 # Always load compatibility stuff.
 load_lib future.exp