diff -ruN virtuoso-opensource-6.1.3/configure.in new/configure.in
--- virtuoso-opensource-6.1.3/configure.in	2011-03-30 01:20:19.000000000 +0200
+++ new/configure.in	2011-09-21 23:04:42.372977092 +0200
@@ -1568,14 +1568,15 @@
 then
     AC_CHECK_HEADER(zlib.h)
     AC_CHECK_LIB(z, main, [with_zlib=yes], [with_zlib=internal])
+    AC_CHECK_LIB(minizip, main, [with_zlib=yes], [with_zlib=internal])
 fi
 if test "x$with_zlib" = "xinternal"
 then
     ZLIB_INC='-I$(top_srcdir)/libsrc/zlib'
     ZLIB_LIB='$(top_builddir)/libsrc/zlib/libz.la'
 else
-    ZLIB_INC=""
-    ZLIB_LIB="-lz"
+    ZLIB_INC=`pkg-config --cflags zlib minizip`
+    ZLIB_LIB=`pkg-config --libs zlib minizip`
 fi
 AC_SUBST(ZLIB_INC)
 AC_SUBST(ZLIB_LIB)
diff -ruN virtuoso-opensource-6.1.3/libsrc/Wi/bif_file.c new/libsrc/Wi/bif_file.c
--- virtuoso-opensource-6.1.3/libsrc/Wi/bif_file.c	2011-02-14 13:30:56.000000000 +0100
+++ new/libsrc/Wi/bif_file.c	2011-09-21 22:44:52.638977417 +0200
@@ -6139,10 +6139,7 @@
   return NULL;
 }
 
-
-#include "zlib/contrib/minizip/unzip.h"
-#include "zlib/contrib/minizip/ioapi.c"
-#include "zlib/contrib/minizip/unzip.c"
+#include "unzip.h"
 
 static caddr_t
 bif_unzip_file (caddr_t * qst, caddr_t * err_ret, state_slot_t ** args)