diff --git a/packages/x11/lib/libX11/build b/packages/x11/lib/libX11/build
index 463c5368e8..2f064b85d9 100755
--- a/packages/x11/lib/libX11/build
+++ b/packages/x11/lib/libX11/build
@@ -27,8 +27,6 @@ export CPPFLAGS_FOR_BUILD="$HOST_CPPFLAGS"
 export CFLAGS_FOR_BUILD="$HOST_CFLAGS -I$SYSROOT_PREFIX/usr/include"
 export LDFLAGS_FOR_BUILD="$HOST_LDFLAGS"
 
-export PKG_CONFIG="$PKG_CONFIG --define-variable=prefix=$SYSROOT_PREFIX/usr"
-
 cd $PKG_BUILD
 
 ./configure --host=$TARGET_NAME \
diff --git a/packages/x11/lib/libX11/patches/libX11-1.5.0-pkg_config.patch b/packages/x11/lib/libX11/patches/libX11-1.5.0-pkg_config.patch
new file mode 100644
index 0000000000..2f03f45302
--- /dev/null
+++ b/packages/x11/lib/libX11/patches/libX11-1.5.0-pkg_config.patch
@@ -0,0 +1,20 @@
+diff -Naur libX11-1.5.0-old/configure.ac libX11-1.5.0-new/configure.ac
+--- libX11-1.5.0-old/configure.ac	2012-06-01 23:37:17.000000000 -0700
++++ libX11-1.5.0-new/configure.ac	2012-06-02 09:13:08.000000000 -0700
+@@ -35,6 +35,7 @@
+ 
+ # Required when PKG_CHECK_MODULES called within an if statement
+ PKG_PROG_PKG_CONFIG
++m4_pattern_allow([^PKG_CONFIG_SYSROOT_DIR$])
+ 
+ if test x"$CC_FOR_BUILD" = x; then
+ 	if test x"$cross_compiling" = xyes; then
+@@ -306,7 +307,7 @@
+ # Find keysymdef.h
+ #
+ AC_MSG_CHECKING([keysym definitions])
+-KEYSYMDEFDIR=`$PKG_CONFIG --variable=includedir xproto`/X11
++KEYSYMDEFDIR=$PKG_CONFIG_SYSROOT_DIR`$PKG_CONFIG --variable=includedir xproto`/X11
+ FILES="keysymdef.h XF86keysym.h Sunkeysym.h DECkeysym.h HPkeysym.h"
+ for i in $FILES; do
+     if test -f "$KEYSYMDEFDIR/$i"; then