Makefile: add wget portability variable - $(WGET)
add tertiary fallback for unavailable package files
fix bracketing of wget calls
cleanup after failed download
add package cdn fallback
Makefile: correctly escape urls for amazon services
package flann: add update script
package vtk: use short pkg version in url
package apr-util: ignore version 1.5.1
package giflib: change update macro to file release instead of repo
package guile: update ignored version
packages hdf4 hdf5: add update script
package libffi: fix update script
package ocaml-native: fix download url and update script
package ocaml-flexdll: fix update script
package protobuf: ignore release candidates in update script
package mdbtools: fix update script
package mingwrt: ignore older version 3.20
package openscenegraph: ignore development version in update script
package wt: fix update script