A trailing comma in a macro call is an empty argument

which should also be counted for the purposes of .NARG.

macros.c

@@ -414,14 +414,16 @@ STREAM         *expandmacro(
     STREAM         *str;
     BUFFER         *buf;
     int             nargs;
+    int             onemore;
 
     args = NULL;
     arg = NULL;
     nargs = 0;      /* for the .NARG directive */
+    onemore = 0;
 
     /* Parse the arguments */
 
-    while (!EOL(*cp)) {
+    while (!EOL(*cp) || onemore) {
         char           *nextcp;
 
         /* Check for named argument */
@@ -464,7 +466,8 @@ STREAM         *expandmacro(
 
         eval_arg(refstr, arg);         /* Check for expression evaluation */
 
-        cp = skipdelim(nextcp);
+        /* If there is a trailing comma, there is an empty last argument */
+        cp = skipdelim_comma(nextcp, &onemore);
     }
 
     /* Now go back and fill in defaults */  {

parse.c

@@ -35,6 +35,21 @@ char           *skipdelim(
     return cp;
 }
 
+/* skipdelim_comma - used to advance between tokens.  Whitespace
+   and one comma are allowed delims.
+   Set *comma depending on whether a comma was skipped. */
+
+char           *skipdelim_comma(
+    char *cp,
+    int  *comma)
+{
+    cp = skipwhite(cp);
+    if (*comma = (*cp == ',')) {
+        cp = skipwhite(cp + 1);
+    }
+    return cp;
+}
+
 /* Parses a string from the input stream. */
 /* If not bracketed by <...> or ^/.../, then */
 /* the string is delimited by trailing comma or whitespace. */

parse.h

@@ -16,6 +16,9 @@ char           *skipwhite(
     char *cp);
 char           *skipdelim(
     char *cp);
+char           *skipdelim_comma(
+    char *cp,
+    int  *comma);
 
 SYMBOL         *get_op(
     char *cp,