build-changes: fix for OSX changes which broke compilation on Linux

Not tested on OSX as far as I know, but I see no reason why it
shouldn't.

Set for  OSX:

set(ENABLE_ICONV ON CACHE BOOL "Whether to build with iconv support or
not")
set(ENABLE_GETTEXT ON CACHE BOOL "Whether to build with gettext support
or not")
set(ENABLE_GLIB_LINUX OFF CACHE BOOL "Whether to build with glib_linux
support or not")
set(ENABLE_GLIB_OSX ON CACHE BOOL "Whether to build with glib_osx
support or not")

"cmake -DENABLE_MYSQL=Off  -DTARGET_DIR=blah .."

All work inspired by @quarnster (unless it's wrong) :P