Make make a little bit more POSIXish with regard to option parsing:

take everything after -- as either a macro assignment or a target.
Note that make still reorders arguments before --: anything starting
with a dash is considered an option, anything which contains an equal
sign is considered a macro assignment and everything else a target.
This still is not POSIX with regard to the options, but it will probably
not change because it has been make's behaviour for ages.
Add a new function Var_Match() that correctly skips a macro call by just
doing the same as Var_Subst() but without producing output. This will help
making the parser more robust.

Patches:	7.190,7.191
Submitted by:	Max Okumoto <okumoto@ucsd.edu>

usr.bin/make/main.c

@@ -241,12 +241,19 @@ static void
 MainParseArgs(int argc, char **argv)
 {
 	int c;
+	Boolean	found_dd = FALSE;
 
 rearg:
 	optind = 1;	/* since we're called more than once */
 	optreset = 1;
 #define OPTFLAGS "ABC:D:E:I:PSV:Xd:ef:ij:km:nqrstvx:"
-	while((c = getopt(argc, argv, OPTFLAGS)) != -1) {
+	for (;;) {
+		if ((optind < argc) && strcmp(argv[optind], "--") == 0) {
+			found_dd = TRUE;
+		}
+		if ((c = getopt(argc, argv, OPTFLAGS)) == -1) {
+			break;
+		}
 		switch(c) {
 
 		case 'A':
@@ -438,11 +445,18 @@ MainParseArgs(int argc, char **argv)
 				 * (*argv) is a single dash, so we
 				 * just ignore it.
 				 */
+			} else if (found_dd) {
+				/*
+				 * Double dash has been found, ignore
+				 * any more options.  But what do we do
+				 * with it?  For now treat it like a target.
+				 */
+				Lst_AtEnd(&create, estrdup(*argv));
 			} else {
 				/*
-				 * (*argv) is a -flag, so backup argv
-				 *  and argc, since getopt() expects
-				 * options to start in the 2nd position.
+				 * (*argv) is a -flag, so backup argv and
+				 * argc.  getopt() expects options to start
+				 * in the 2nd position.
 				 */
 				argc++;
 				argv--;

usr.bin/make/var.c

@@ -108,6 +108,7 @@ typedef struct VarParser {
 	const char	*ptr;		/* current parser pos in input str */
 	GNode		*ctxt;
 	Boolean		err;
+	Boolean		execute;
 } VarParser;
 static char *VarParse(VarParser *, Boolean *);
 
@@ -764,7 +765,8 @@ VarGetPattern(VarParser *vp, int delim, int *flags, VarPattern *patt)
 					vp->ptr,
 					vp->ptr,
 					vp->ctxt,
-					vp->err
+					vp->err,
+					vp->execute
 				};
 				char   *rval;
 				Boolean rfree;
@@ -1229,10 +1231,13 @@ ParseModifier(VarParser *vp, char startc, Var *v, Boolean *freeResult)
 				    (vp->ptr[1] == 'h') &&
 				    (vp->ptr[2] == endc || vp->ptr[2] == ':')) {
 					const char	*error;
-					Buffer		*buf;
 
-					buf = Cmd_Exec(value, &error);
-					newStr = Buf_Peel(buf);
+					if (vp->execute) {
+						newStr = Buf_Peel(
+						    Cmd_Exec(value, &error));
+					} else {
+						newStr = estrdup("");
+					}
 
 					if (error)
 						Error(error, value);
@@ -1560,7 +1565,8 @@ VarParseLong(VarParser *vp, Boolean *freeResult)
 				vp->ptr,
 				vp->ptr,
 				vp->ctxt,
-				vp->err
+				vp->err,
+				vp->execute
 			};
 			char	*rval;
 			Boolean	rfree;
@@ -1691,7 +1697,8 @@ Var_Parse(const char input[], GNode *ctxt, Boolean err,
 		input,
 		input,
 		ctxt,
-		err
+		err,
+		TRUE
 	};
 	char		*value;
 
@@ -1700,6 +1707,34 @@ Var_Parse(const char input[], GNode *ctxt, Boolean err,
 	return (value);
 }
 
+/*
+ *
+ * Results:
+ *	The number of characters in the specification.  For invalid
+ *	specifications, this is just 2 to skip the '$' and the
+ *	following letter, or 1 if '$' was the last character in the
+ *	string.
+ */
+size_t
+Var_Match(const char input[], GNode *ctxt)
+{
+	VarParser	vp = {
+		input,
+		input,
+		ctxt,
+		FALSE,
+		FALSE
+	};
+	char		*value;
+	Boolean		freeResult;
+
+	value = VarParse(&vp, &freeResult);
+	if (freeResult) {
+		free(value);
+	}
+	return (vp.ptr - vp.input);
+}
+
 /*-
  *-----------------------------------------------------------------------
  * Var_Subst  --
@@ -1746,7 +1781,8 @@ Var_Subst(const char *str, GNode *ctxt, Boolean err)
 				str,
 				str,
 				ctxt,
-				err
+				err,
+				TRUE
 			};
 			char	*rval;
 			Boolean	rfree;
@@ -1883,7 +1919,8 @@ Var_SubstOnly(const char *var, const char *str, GNode *ctxt, Boolean err)
 					str,
 					str,
 					ctxt,
-					err
+					err,
+					TRUE
 				};
 				char	*rval;
 				Boolean	rfree;

usr.bin/make/var.h

@@ -94,6 +94,7 @@ void Var_Delete(const char *, struct GNode *);
 void Var_Dump(const struct GNode *);
 Boolean Var_Exists(const char *, struct GNode *);
 void Var_Init(char **);
+size_t Var_Match(const char [], struct GNode *);
 char *Var_Parse(const char *, struct GNode *, Boolean, size_t *, Boolean *);
 char *Var_Quote(const char *);
 void Var_Set(const char *, const char *, struct GNode *);