Separate buildtree and buildpkg code

Code is now located via BUILDPKG_SCRIPTS while the buildtree is located
via BUILDPKG_BASE.

build.sh.generic

@@ -1,7 +1,7 @@
 #!/bin/bash
 # This is a buildpkg build.sh script
 # build.sh helper functions
-. ${BUILDPKG_BASE}/scripts/build.sh.functions
+. ${BUILDPKG_SCRIPTS}/build.sh.functions
 #
 ###########################################################
 # Check the following 4 variables before running the script
@@ -13,7 +13,7 @@ source[0]=$topdir-$version.tar.gz
 patch[0]=
 
 # Source function library
-. ${BUILDPKG_BASE}/scripts/buildpkg.functions
+. ${BUILDPKG_SCRIPTS}/buildpkg.functions
 
 reg prep
 prep()