Fix POSIX-isms in gdb.base/shell.exp

Some recent tests added to gdb.base/shell.exp have been failing on
Windows host due to assumptions that the shell is a POSIX variant.  On
Windows, GDB uses CMD.EXE via the system() call to run shell commands
instead.

There seems to be no obvious CMD.EXE equivalent for "kill -2 $$" to
signal the shell process, so this patch skips those tests on Windows
host.  The second problem addressed here is that CMD.EXE only
recognizes double quotes, not single quotes; that change can be made
unconditionally since POSIX shells recognize double quotes as well.

2020-07-16  Sandra Loosemore  <sandra@codesourcery.com>

	gdb/testsuite/
	* gdb.base/shell.exp: Skip pipe tests dependent on sh on Windows host.
	Use double quotes instead of single quotes.

2 files changed, 21 insertions, 10 deletions

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 5eb9847..e20e026 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-07-16  Sandra Loosemore  <sandra@codesourcery.com>
+
+	* gdb.base/shell.exp: Skip pipe tests dependent on sh on Windows host.
+	Use double quotes instead of single quotes.
+
 2020-07-16  Caroline Tice  <cmtice@google.com>
 
 	* gdb.dwarf2/dw5-rnglist-test.cc: New file.
diff --git a/gdb/testsuite/gdb.base/shell.exp b/gdb/testsuite/gdb.base/shell.exp
index f656077..ad36f6b 100644
--- a/gdb/testsuite/gdb.base/shell.exp
+++ b/gdb/testsuite/gdb.base/shell.exp
@@ -34,9 +34,12 @@ gdb_test_no_output "! exit 1"
 gdb_test "p \$_shell_exitcode" " = 1" "shell fail exitcode"
 gdb_test "p \$_shell_exitsignal" " = void" "shell fail exitsignal"
 
-gdb_test_no_output "! kill -2 $$"
-gdb_test "p \$_shell_exitcode" " = void" "shell interrupt exitcode"
-gdb_test "p \$_shell_exitsignal" " = 2" "shell interrupt exitsignal"
+# This test will not work when the shell is CMD.EXE.
+if { ! [ishost *-*-mingw*] } {
+    gdb_test_no_output "! kill -2 $$"
+    gdb_test "p \$_shell_exitcode" " = void" "shell interrupt exitcode"
+    gdb_test "p \$_shell_exitsignal" " = 2" "shell interrupt exitsignal"
+}
 
 # Define the user command "foo", used to test "pipe" command.
 gdb_test_multiple "define foo" "define foo" {
@@ -67,16 +70,16 @@ gdb_test "|foo|grep truc|wc -l" "1" "no space around pipe char"
 gdb_test "echo coucou\\n" "coucou" "echo coucou"
 gdb_test "||wc -l" "1" "repeat previous command"
 
-gdb_test "| -d ! echo this contains a | character\\n ! sed -e 's/|/PIPE/'" \
+gdb_test "| -d ! echo this contains a | character\\n ! sed -e \"s/|/PIPE/\"" \
     "this contains a PIPE character" "alternate 1char delim"
 
-gdb_test "|-d ! echo this contains a | character\\n!sed -e 's/|/PIPE/'" \
+gdb_test "|-d ! echo this contains a | character\\n!sed -e \"s/|/PIPE/\"" \
     "this contains a PIPE character" "alternate 1char delim, no space"
 
-gdb_test "| -d !!! echo this contains a | character\\n !!! sed -e 's/|/PIPE/'" \
+gdb_test "| -d !!! echo this contains a | character\\n !!! sed -e \"s/|/PIPE/\"" \
     "this contains a PIPE character" "alternate 3char delim"
 
-gdb_test "|-d !!! echo this contains a | character\\n!!!sed -e 's/|/PIPE/'" \
+gdb_test "|-d !!! echo this contains a | character\\n!!!sed -e \"s/|/PIPE/\"" \
     "this contains a PIPE character" "alternate 3char delim, no space"
 
 # Convenience variables with pipe command.
@@ -88,9 +91,12 @@ gdb_test "|p 123| exit 1" ""
 gdb_test "p \$_shell_exitcode" " = 1" "pipe fail exitcode"
 gdb_test "p \$_shell_exitsignal" " = void" "pipe fail exitsignal"
 
-gdb_test "|p 123| kill -2 $$" ""
-gdb_test "p \$_shell_exitcode" " = void" "pipe interrupt exitcode"
-gdb_test "p \$_shell_exitsignal" " = 2" "pipe interrupt exitsignal"
+# This test will not work when the shell is CMD.EXE.
+if { ! [ishost *-*-mingw*] } {
+    gdb_test "|p 123| kill -2 $$" ""
+    gdb_test "p \$_shell_exitcode" " = void" "pipe interrupt exitcode"
+    gdb_test "p \$_shell_exitsignal" " = 2" "pipe interrupt exitsignal"
+}
 
 # Error handling verifications.
 gdb_test "|" "Missing COMMAND" "all missing"