Handle multiline macro definitions

Compress them onto one line for printing in the generated table.

https://github.com/krb5/krb5/commit/760155906bc47163bac1fb5622034a9d53e15294
Author: Ben Kaduk <kaduk@mit.edu>
Commit: 760155906bc47163bac1fb5622034a9d53e15294
Branch: master
 doc/tools/doxybuilder_types.py |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)