gcc: Implement -Wmost for compatibility with clang.

This is equivalent to -Wall -Wno-parentheses.

Obtained from:	Apple GCC 4.2 - 5531
MFC after:	1 week

contrib/gcc/c-opts.c

@@ -385,12 +385,17 @@ c_common_handle_option (size_t scode, const char *arg, int value)
       break;
 
     case OPT_Wall:
+      /* APPLE LOCAL -Wmost */
+    case OPT_Wmost:
       set_Wunused (value);
       set_Wformat (value);
       set_Wimplicit (value);
       warn_char_subscripts = value;
       warn_missing_braces = value;
-      warn_parentheses = value;
+      /* APPLE LOCAL begin -Wmost --dpatel */
+      if (code != OPT_Wmost) 
+	warn_parentheses = value;
+      /* APPLE LOCAL end -Wmost --dpatel */
       warn_return_type = value;
       warn_sequence_point = value;	/* Was C only.  */
       if (c_dialect_cxx ())

contrib/gcc/c.opt

@@ -284,6 +284,12 @@ Wmissing-prototypes
 C ObjC Var(warn_missing_prototypes)
 Warn about global functions without prototypes
 
+; APPLE LOCAL begin -Wmost
+Wmost
+C ObjC C++ ObjC++ 
+Like -Wall but without -Wparentheses
+; APPLE LOCAL end -Wmost
+
 Wmultichar
 C ObjC C++ ObjC++
 Warn about use of multi-character character constants

contrib/gcc/doc/invoke.texi

@@ -222,6 +222,8 @@ in the following sections.
 -Wmain  -Wmissing-braces  -Wmissing-field-initializers @gol
 -Wmissing-format-attribute  -Wmissing-include-dirs @gol
 -Wmissing-noreturn @gol
+@c APPLE LOCAL -Wmost
+-Wmost (APPLE ONLY) @gol
 -Wno-multichar  -Wnonnull  -Wno-overflow @gol
 -Woverlength-strings  -Wpacked  -Wpadded @gol
 -Wparentheses  -Wpointer-arith  -Wno-pointer-to-int-cast @gol
@@ -2652,7 +2654,12 @@ warnings about constructions that some users consider questionable, and
 that are easy to avoid (or modify to prevent the warning), even in
 conjunction with macros.  This also enables some language-specific
 warnings described in @ref{C++ Dialect Options}.
+@c APPLE LOCAL begin -Wmost
+@item -Wmost
+@opindex Wmost
+This is equivalent to -Wall -Wno-parentheses.  (Apple compatible)
 @end table
+@c APPLE LOCAL end -Wmost
 
 The following @option{-W@dots{}} options are not implied by @option{-Wall}.
 Some of them warn about constructions that users generally do not