RFA: maybe prototyped

[Michael Elizabeth Chastain]

Feedback:

. TYPE_FLAG_PROTOTYPED is documented in doc/gdbint.texinfo
  so that needs updating.

. I proofread the patch and found nothing else to kvetch about.

. I ran the test suite (native i686-pc-linux-gnu, v2 and v3 gcc compilers,
  stabs debugging format) and it found nothing to kvetch about either.
  I paid particular attention to callfuncs.c / t_float_values tests,
  which are the explicitly non-prototyped tests.

. Aside from the doco lacuna, looks okay by me.

Michael C