Add patch in order to fix the build with gcc 4.1 and set WRKSRC accordingly

Reported by:	kris

sysutils/pdixtract/Makefile

@@ -14,6 +14,7 @@ DISTNAME=	PDITOOL
 MAINTAINER=	markus@FreeBSD.org
 COMMENT=	Extracts or converts .pdi file sets to .iso
 
+WRKSRC=		${WRKDIR}
 USE_ZIP=	yes
 
 PLIST_FILES=	bin/pdixtract

sysutils/pdixtract/files/patch-pdixtract.c

@@ -0,0 +1,28 @@
+--- pdixtract.c.orig	Thu Dec 14 00:18:17 2006
++++ pdixtract.c	Thu Dec 14 00:25:55 2006
+@@ -79,6 +79,12 @@
+         char name                       [1];
+ };
+ 
++struct filedesc {
++  char *name;
++  size_t size; /* size in extents */
++  size_t extent;
++  int hits; /* flag for individual file selection */
++};
+ 
+ char buffer[BUFFSIZE];
+ struct filedesc files[MAX_FILES];
+@@ -106,12 +112,6 @@
+   exit(1);
+ }
+ 
+-struct filedesc {
+-  char *name;
+-  size_t size; /* size in extents */
+-  size_t extent;
+-  int hits; /* flag for individual file selection */
+-};
+ 
+ 
+ /* helper for qsort, compares extents of 2 filedescs */