[PATCH] Fix .opt file parsing to allow nested parentheses in option property arguments.

[Dave Korn <dave dot korn dot cygwin at googlemail dot com>]

    Hi all,

  I ran into difficulty when I wanted to use the preprocessor "defined (X)"
operator in a Condition(...) option property.  The simple parsing in the awk
script got fooled by the closing parenthesis of the defined operator, taking
it for the end of the option property argument itself, and I ended up with a
line in $objdir/gcc/options.c looking like

#if defined (X

... which of course didn't work.  Rather than attempting to count the depth of
nested parentheses using a regex language I figured the simple approach would
just be to invent a way of quoting the argument string, and picked on curly
braces, which aren't currently used anywhere in .opt files (at least according
to "find gcc/ -name '*.opt' | xargs grep '{'", anyway).

gcc/ChangeLog:

	* opt-functions.awk (opt_args): Allow argument to be enclosed in
	curly braces.
	* doc/options.texi (Option properties):  Mention new quoting syntax.

  Tested by running the scripts manually and visually inspecting options.c,
then completing a bootstrap, and docs tested by "make doc info dvi html pdf".
 OK for head?

    cheers,
      DaveK

Index: gcc/opt-functions.awk
===================================================================
--- gcc/opt-functions.awk	(revision 149338)
+++ gcc/opt-functions.awk	(working copy)
@@ -41,7 +41,13 @@ function opt_args(name, flags)
 	if (flags !~ " " name "\\(")
 		return ""
 	sub(".* " name "\\(", "", flags)
-	sub("\\).*", "", flags)
+	if (flags ~ "^{")
+	{
+		sub ("^{", "", flags)
+		sub("}\\).*", "", flags)
+	}
+	else
+		sub("\\).*", "", flags)
 
 	return flags
 }
Index: gcc/doc/options.texi
===================================================================
--- gcc/doc/options.texi	(revision 149338)
+++ gcc/doc/options.texi	(working copy)
@@ -84,8 +84,17 @@ configurations and yet the masks always need to be
 @node Option properties
 @section Option properties
 
-The second field of an option record can specify the following properties:
+The second field of an option record can specify any of the following
+properties.  When an option takes an argument, it is enlosed in parentheses
+following the option property name.  The parser that handles option files
+is quite simplistic, and will be tricked by any nested parentheses within
+the argument text itself; in this case, the entire option argument can
+be wrapped in curly braces within the parentheses to demarcate it, e.g.:
 
+@smallexample
+Condition(@{defined (USE_CYGWIN_LIBSTDCXX_WRAPPERS)@})
+@end smallexample
+
 @table @code
 @item Common
 The option is available for all languages and targets.