commit 99368862e44740ff4fd33760893f04e14f9dbdf1
Author: Felix Fietkau <nbd@openwrt.org>
Date:   Tue Jul 31 00:52:27 2007 +0000

    Port the mbsd_multi patch from freewrt, which adds -fhonour-copts. This will emit warnings in packages that don't use our target cflags properly
    
    SVN-Revision: 8256

	This patch brings over a feature from MirBSD:
	* -fhonour-copts
	  If this option is not given, it's warned (depending
	  on environment variables). This is to catch errors
	  of misbuilt packages which override CFLAGS themselves.

	This patch was authored by Thorsten Glaser <tg at mirbsd.de>
	with copyright assignment to the FSF in effect.

--- a/gcc/c-family/c-opts.cc
+++ b/gcc/c-family/c-opts.cc
@@ -104,6 +104,9 @@ static size_t include_cursor;
 /* Whether any standard preincluded header has been preincluded.  */
 static bool done_preinclude;
 
+/* Check if a port honours COPTS.  */
+static int honour_copts = 0;
+
 static void handle_OPT_d (const char *);
 static void set_std_cxx98 (int);
 static void set_std_cxx11 (int);
@@ -475,6 +478,12 @@ c_common_handle_option (size_t scode, co
       flag_no_builtin = !value;
       break;
 
+    case OPT_fhonour_copts:
+      if (c_language == clk_c) {
+        honour_copts++;
+      }
+      break;
+
     case OPT_fconstant_string_class_:
       constant_string_class_name = arg;
       break;
@@ -1228,6 +1237,47 @@ c_common_init (void)
       return false;
     }
 
+  if (c_language == clk_c) {
+    char *ev = getenv ("GCC_HONOUR_COPTS");
+    int evv;
+    if (ev == NULL)
+      evv = -1;
+    else if ((*ev == '0') || (*ev == '\0'))
+      evv = 0;
+    else if (*ev == '1')
+      evv = 1;
+    else if (*ev == '2')
+      evv = 2;
+    else if (*ev == 's')
+      evv = -1;
+    else {
+      warning (0, "unknown GCC_HONOUR_COPTS value, assuming 1");
+      evv = 1; /* maybe depend this on something like MIRBSD_NATIVE?  */
+    }
+    if (evv == 1) {
+      if (honour_copts == 0) {
+        error ("someone does not honour COPTS at all in lenient mode");
+        return false;
+      } else if (honour_copts != 1) {
+        warning (0, "someone does not honour COPTS correctly, passed %d times",
+         honour_copts);
+      }
+    } else if (evv == 2) {
+      if (honour_copts == 0) {
+        error ("someone does not honour COPTS at all in strict mode");
+        return false;
+      } else if (honour_copts != 1) {
+        error ("someone does not honour COPTS correctly, passed %d times",
+         honour_copts);
+        return false;
+      }
+    } else if (evv == 0) {
+      if (honour_copts != 1)
+        inform (UNKNOWN_LOCATION, "someone does not honour COPTS correctly, passed %d times",
+         honour_copts);
+    }
+  }
+
   return true;
 }
 
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -1837,6 +1837,9 @@ C++ ObjC++ Optimization Alias(fexception
 fhonor-std
 C++ ObjC++ WarnRemoved
 
+fhonour-copts
+C ObjC C++ ObjC++ RejectNegative
+
 fhosted
 C ObjC
 Assume normal C execution environment.
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -1801,6 +1801,9 @@ fharden-conditional-branches
 Common Var(flag_harden_conditional_branches) Optimization
 Harden conditional branches by checking reversed conditions.
 
+fhonour-copts
+Common RejectNegative
+
 ; Nonzero means ignore `#ident' directives.  0 means handle them.
 ; Generate position-independent code for executables if possible
 ; On SVR4 targets, it also controls whether or not to emit a
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -10062,6 +10062,17 @@ This option is only supported for C and
 @option{-Wall} and by @option{-Wpedantic}, which can be disabled with
 @option{-Wno-pointer-sign}.
 
+@item -fhonour-copts
+@opindex fhonour-copts
+If @env{GCC_HONOUR_COPTS} is set to 1, abort if this option is not
+given at least once, and warn if it is given more than once.
+If @env{GCC_HONOUR_COPTS} is set to 2, abort if this option is not
+given exactly once.
+If @env{GCC_HONOUR_COPTS} is set to 0 or unset, warn if this option
+is not given exactly once.
+The warning is quelled if @env{GCC_HONOUR_COPTS} is set to @samp{s}.
+This flag and environment variable only affect the C language.
+
 @opindex Wstack-protector
 @opindex Wno-stack-protector
 @item -Wstack-protector
--- a/gcc/opts.cc
+++ b/gcc/opts.cc
@@ -2767,6 +2767,9 @@ common_handle_option (struct gcc_options
       add_comma_separated_to_vector (&opts->x_flag_ignored_attributes, arg);
       break;
 
+    case OPT_fhonour_copts:
+      break;
+
     case OPT_Werror:
       dc->warning_as_error_requested = value;
       break;