don't overwrite CFLAGS, add to it
win: help clwrapper link zlib when using precompiled packages
win: build zlib
clean ups/comments
win: add libtool to packages and build it
win: shared & static gstreamer libs

don't know if this is necessary, but this was part of the overall config
I had
when I finally got gst-plugins-base to build correctly.
win: gst-plugins-base - don't add linker flags, define inline to __inline
win: gst-plugins-base - don't use GST_CAT_PERFORMANCE

it  leads to unresolved symbols when linking
win: gst-plugins-base - MSVC2010 doesn't have the "rint" function