Allow defining a user command inside a user command

PR gdb/11750 concerns defining a command inside a user commnad, like:

    define outer
      define inner
	echo hi\n
      end
    end

This patch adds this capability to gdb.

ChangeLog
2018-05-04  Tom Tromey  <tom@tromey.com>

	PR gdb/11750:
	* cli/cli-script.h (enum command_control_type) <define_control>:
	New constant.
	* cli/cli-script.c (multi_line_command_p): Handle define_control.
	(build_command_line, execute_control_command_1)
	(process_next_line): Likewise.
	(do_define_command): New function, extracted from define_command.
	(define_command): Use it.

testsuite/ChangeLog
2018-05-04  Tom Tromey  <tom@tromey.com>

	PR gdb/11750:
	* gdb.base/define.exp: Test defining a user command inside a user
	command.
	* gdb.base/commands.exp (define_if_without_arg_test): Test "define".

1 files changed, 2 insertions, 2 deletions

diff --git a/gdb/testsuite/gdb.base/commands.exp b/gdb/testsuite/gdb.base/commands.exp
index b33e5124ec7..259b89b803d 100644
--- a/gdb/testsuite/gdb.base/commands.exp
+++ b/gdb/testsuite/gdb.base/commands.exp
@@ -1014,7 +1014,7 @@ proc_with_prefix redefine_backtrace_test {} {
 # Test using "if" and "while" without args when building a command list.
 
 proc define_if_without_arg_test {} {
-    foreach cmd {if while} {
+    foreach cmd {if while define} {
 	set test "define some_command_$cmd"
 	gdb_test_multiple $test $test {
 	    -re "End with"  {
@@ -1022,7 +1022,7 @@ proc define_if_without_arg_test {} {
 	    }
 	}
 
-	gdb_test "$cmd" "if/while commands require arguments." "type $cmd without args"
+	gdb_test "$cmd" "$cmd command requires an argument." "type $cmd without args"
     }
 }