raw_ostream has not afforded a lot of flexibility in terms of
how to format numbers when outputting. Wrap this all up into
a set of low level helper functions that can be used to output
numbers with arbitrary precision, alignment, format, etc and
then update raw_ostream to use these functions.
This will be useful for upcoming improvements to llvm's string
formatting libraries, but are still useful independently.
Differential Revision: https://reviews.llvm.org/D25497
llvm-svn: 284425
1a9ea1b68a