Rearrange logic to address type mismatch spotted by clang 15

misc/magicpoint/Makefile

@@ -1,7 +1,7 @@
 COMMENT=	X11-based presentation tool
 
 DISTNAME=	magicpoint-1.09a
-REVISION=	3
+REVISION=	4
 EPOCH=		0
 CATEGORIES=	misc productivity
 MASTER_SITES=	ftp://sh.wide.ad.jp/WIDE/free-ware/mgp/

misc/magicpoint/patches/patch-mgp_c

@@ -0,0 +1,25 @@
+Fix with clang 15: invalid pointer to integer conversion.
+
+Index: mgp.c
+--- mgp.c.orig
++++ mgp.c
+@@ -448,16 +448,16 @@ genhtml(start_page)
+ 	char *childdebug;
+ 	char convdb[][3][16] = {{ "jpg", "cjpeg", "djpeg" },
+ 				{ "png", "pnmtopng", "pngtopnm" },
+-				{ NULL, NULL, NULL }};
++				{ "", "", "" }};
+ 	int inum = 0;
+ 
+ 	/* check image type */
+ 	if (htmlimage) {
+-		for (inum = 0; *convdb[inum] != NULL; inum++) {
++		for (inum = 0; **convdb[inum] != '\0'; inum++) {
+ 			if (strcmp(*convdb[inum], htmlimage) == 0)
+ 				break;
+ 		}
+-		if (*convdb[inum] == NULL) {
++		if (**convdb[inum] == '\0') {
+ 			fprintf(stderr, "unknwon image type %s.\n", htmlimage);
+ 			cleanup(-1);
+ 		}