xcowsay: update to 1.5.1

Also, remove CFLAGS because C99 is now detected at configure time, and
add an upstreamed patch so configuration files are properly read on
unsigned char archs (arm, powerpc). Thanks to bcallah@ for code
correctness hint!

OK gnezdo@

games/xcowsay/Makefile

@@ -1,9 +1,8 @@
-# $OpenBSD: Makefile,v 1.16 2020/03/03 16:06:12 kmos Exp $
+# $OpenBSD: Makefile,v 1.17 2020/10/13 15:58:06 cwen Exp $
 
 COMMENT =		displays a cute cow and message on your desktop
-DISTNAME =		xcowsay-1.5
+DISTNAME =		xcowsay-1.5.1
 CATEGORIES =		games
-REVISION =		0
 
 HOMEPAGE =		https://www.doof.me.uk/xcowsay/
 
@@ -18,6 +17,5 @@ MASTER_SITES =		http://www.nickg.me.uk/files/
 CONFIGURE_STYLE =	gnu
 
 LIB_DEPENDS =		x11/gtk+3
-CFLAGS +=		-std=c99
 
 .include <bsd.port.mk>

games/xcowsay/distinfo

@@ -1,2 +1,2 @@
-SHA256 (xcowsay-1.5.tar.gz) = PqRaRTE15NTreb1YfCms1O4Ixf0+1AmbEU+FLwxQyl8=
-SIZE (xcowsay-1.5.tar.gz) = 285463
+SHA256 (xcowsay-1.5.1.tar.gz) = wypsfAp634wbaAI+fxzmr3J5AmvQzChVi/wp/BPxiA0=
+SIZE (xcowsay-1.5.1.tar.gz) = 287843

games/xcowsay/patches/patch-src_config_file_c

@@ -0,0 +1,18 @@
+$OpenBSD: patch-src_config_file_c,v 1.1 2020/10/13 15:58:06 cwen Exp $
+
+Allow to properly read the configuration files on archs where char is unsigned
+(arm, ppc) as EOF is usually -1.
+See https://github.com/nickg/xcowsay/commit/666ad99
+
+Index: src/config_file.c
+--- src/config_file.c.orig
++++ src/config_file.c
+@@ -78,7 +78,7 @@ static token_t next_token(FILE *f, strbuf_t* sbuf, int
+    bool skip_to_eol = false;
+    bool in_quotes = false;
+    for (;;) {
+-      char next = fgetc(f);
++      int next = fgetc(f);
+       if (EOF == next)
+          return (has_chars(sbuf) && !skip_to_eol) ? tTOKEN : tEOF;
+       else if ('\n' == next) {