FIX games/corewars -fno-common build error

Diff below fixes the build error for games/corewars. While here move
HOMEPAGE to https.

It starts on amd64...

Comments/OK?

diff --git Makefile Makefile
index f4bb9e4e1e7..d179e567ee2 100644
--- Makefile
+++ Makefile
@@ -3,11 +3,11 @@
COMMENT= computer simulation game

DISTNAME= corewars-0.9.13
-REVISION= 9
+REVISION= 10

CATEGORIES= games x11

-HOMEPAGE= http://corewars.org/
+HOMEPAGE= https://corewars.org/

# GPLv2
PERMIT_PACKAGE= Yes
diff --git patches/patch-src_parser-cw_c patches/patch-src_parser-cw_c
new file mode 100644
index 00000000000..ecced62a75b
--- /dev/null
+++ patches/patch-src_parser-cw_c
@@ -0,0 +1,18 @@
+$OpenBSD$
+
+Fix -fno-common build error.
+
+Index: src/parser-cw.c
+--- src/parser-cw.c.orig
++++ src/parser-cw.c
+@@ -32,8 +32,8 @@
+ #include "program-cw.h"
+ #include "options.h"
+
+- int current_line;
+- struct cw_line *root_line;
++ extern int current_line;
++ extern struct cw_line *root_line;
+ char cw_error_message[1024];
+
+ void cw_error (char *s);