Makefile: add proxies to env whitelist
doc update: add proxies to env whitelist and re-align unset command
Makefile: use cut instead of sed for env var list
Makefile: add explicit failed download message
package m4: gets has been removed from recent glibc
package vtk: fix configure of native build for missing X11/OSMesa libraries
Merge pull request #235 from sikoragmbh/vtk6-fix-native-conf

package vtk6: fix configure of native build for missing X11/OSMesa libraries
package vtk6: fix for standalone native build without rendering
package vtk6: reverse standalone patch for cross build
packages binutils dbus gcc gettext libiconv: enable/disable native builds
package gcc: add gcc to list of symlinks for native build
Revert "package vtk6: reverse standalone patch for cross build"

This reverts commit 76a176ba178d72440fb6504bcf89f5129a7808ed.
Revert "package vtk6: fix for standalone native build without rendering"

This reverts commit b7a8dc442fb51e156827e26c03c52a99b09912ed.
package vtk6: drop native OpenGL dependency
package sqlite: fix checksum
Merge pull request #238 from sikoragmbh/vtk6-fix-gl

package vtk6: fix native opengl dependency
update qt5 packages