[ports-gcc] Unbreak graphics/aspect-crop

> http://build-failures.rhaalovely.net//powerpc/2019-07-14/graphics/aspect-crop.log
> http://build-failures.rhaalovely.net/sparc64/2019-07-11/graphics/aspect-crop.log

There is just a missing header here. Once added it builds fine on
macppc [0].

Comments/feedback are welcome!

Charlène.


[0] https://bin.charlenew.xyz/aspect-crop.log


Index: Makefile
===================================================================
RCS file: /cvs/ports/graphics/aspect-crop/Makefile,v
retrieving revision 1.3
diff -u -p -u -p -r1.3 Makefile
--- Makefile 29 Jun 2019 20:43:04 -0000 1.3
+++ Makefile 26 Jul 2019 12:48:47 -0000
@@ -7,6 +7,7 @@ MAINTAINER = Marc Espie <espie@openbsd.
GH_PROJECT = aspect-crop
GH_TAGNAME = 1.7
GH_ACCOUNT = marcespie
+REVISION = 0

MODULES = x11/qt5

Index: patches/patch-system_C
===================================================================
RCS file: patches/patch-system_C
diff -N patches/patch-system_C
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ patches/patch-system_C 26 Jul 2019 12:48:47 -0000
@@ -0,0 +1,15 @@
+$OpenBSD$
+
+ports-gcc: add missing header
+
+Index: system.C
+--- system.C.orig
++++ system.C
+@@ -15,6 +15,7 @@
+ */
+ #include <sys/wait.h>
+ #include <signal.h>
++#include <string.h>
+ #include <iostream>
+ #include <unistd.h>
+