during engraving, spaces were counted instead of non-spaces

2015 commit 27d8b631cd incorrectly altered a test

	/* Chop engraving down to size if necessary */
	if (len > maxelen) {
	    for (sp = ebuf; (maxelen && *sp); sp++)
->		if (!isspace(*sp)) maxelen--;
	    if (!maxelen && *sp) {
		*sp = (char)0;
		if (multi) nomovemsg = "You cannot write any more.";

was changed to:

	/* Chop engraving down to size if necessary */
        if (len > maxelen) {
	    for (sp = ebuf; (maxelen && *sp); sp++)
->		if (*sp == ' ') maxelen--;
	    if (!maxelen && *sp) {
		*sp = (char)0;
		if (multi) nomovemsg = "You cannot write any more.";

Fixes #457

doc/fixes37.0

@@ -379,6 +379,7 @@ prevent wish request "death wand" from matching Death monster and producing a
 	random wand instead of a wand of death
 grammar bit: "you hear a [AEF] note squeak in the distance" (should be "an")
 curses interface failed to honor menu_xxx option settings for menu interaction
+during engraving, spaces were counted instead of non-spaces
 
 
 Fixes to 3.7.0-x Problems that Were Exposed Via git Repository

src/engrave.c

@@ -1143,7 +1143,7 @@ doengrave(void)
     /* Chop engraving down to size if necessary */
     if (len > maxelen) {
         for (sp = ebuf; maxelen && *sp; sp++)
-            if (*sp == ' ')
+            if (!(*sp == ' '))
                 maxelen--;
         if (!maxelen && *sp) {
             *sp = '\0';