I occasionally have a complex set of variable mods that I want to use 
in multiple places and it would be handy to specify these in variable
as in (trivial example I know):

MODS=S,A,a,

V=Abc

all:
	@echo V=${V:${MODS}}

it would be nice if this printed 'abc' rather than an error about $
being an unknown modifier.  The patch below does this (and all the
unit tests still pass), but I'm not convinced it is right wrt cleanup.
I'd appreciate a 2nd opinion.

Thanks
--sjg

--- var.c.~1~	Sat Sep  3 15:15:09 2005
+++ var.c	Fri Jan 20 16:58:52 2006
@@ -1890,6 +1890,7 @@ Var_Parse(const char *str, GNode *ctxt, 
 	  Boolean *freePtr)
 {
     const char	   *tstr;    	/* Pointer into str */
+    const char	   *tstr2;	/* Secondary tstr if we need to recurse  */
     Var	    	   *v;	    	/* Variable in invocation */
     const char     *cp;    	/* Secondary pointer into str (place marker
 				 * for tstr) */
@@ -1915,6 +1916,7 @@ Var_Parse(const char *str, GNode *ctxt, 
     start = str;
     parsestate.oneBigWord = FALSE;
     parsestate.varSpace = ' ';	/* word separator */
+    tstr2 = NULL;
 
     if (str[1] != PROPEN && str[1] != BROPEN) {
 	/*
@@ -2257,6 +2259,9 @@ Var_Parse(const char *str, GNode *ctxt, 
 	tstr++;
 	delim = '\0';
 
+	if (*tstr == '$') {
+	    tstr = tstr2 = Var_Subst(NULL, tstr, ctxt, err);
+	}
 	while (*tstr && *tstr != endc) {
 	    char	*newStr;    /* New value to return */
 	    char	termc;	    /* Character which terminated scan */
@@ -3235,6 +3240,8 @@ cleanup:
     *lengthPtr = cp - start + 1;
     if (*freePtr)
 	free(nstr);
+    if (tstr2)
+	free(tstr2);
     if (delim != '\0')
 	Error("Unclosed substitution for %s (%c missing)",
 	      v->name, delim);