largefile: enforce largefile autotools flags
largefile: enforce largefile autotools flags

Make sure we enable largefile support when the useflag is enabled
by forcing largefile specific autotools flags to the correct settings.

without this e.g. libsndfile would not be built with largefile
support even though the configure switch was on.

sknsean/core,sknsean/core,sknsean/core,sknsean/core,sknsean/core