[gdb/testsuite] Add basic lmap for tcl < 8.6

With test-case gdb.dwarf2/dw2-abs-hi-pc.exp and tcl 8.5, I run into:
...
ERROR: tcl error sourcing gdb/testsuite/gdb.dwarf2/dw2-abs-hi-pc.exp.
ERROR: invalid command name "lmap"
    while executing
"::gdb_tcl_unknown lmap i {dw2-abs-hi-pc.c dw2-abs-hi-pc-hello.c \
  dw2-abs-hi-pc-world.c} { expr { "$srcdir/$subdir/$i" } }"
...

Fix this by adding basic lmap support for tcl version < 8.6.

Tested on x86_64-linux.

1 files changed, 15 insertions, 0 deletions

diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index b59b435..9d711e8 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -1516,6 +1516,21 @@ if { [tcl_version_at_least 8 5] == 0 } {
     }
 }
 
+if { [tcl_version_at_least 8 6] == 0 } {
+    # lmap was added in tcl 8.6.  Only add if missing.
+
+    # Note that we only implement the simple variant for now.
+    proc lmap { varname list body } {
+	set res {}
+	foreach val $list {
+	    uplevel 1 "set $varname $val"
+	    lappend res [uplevel 1 $body]
+	}
+
+	return $res
+    }
+}
+
 # gdb_test_no_output [-prompt PROMPT_REGEXP] [-nopass] COMMAND [MESSAGE]
 # Send a command to GDB and verify that this command generated no output.
 #