[RFA 0/5] Use language mode in 'info [functions|variables|types]|rbreak'

[Philippe Waroquiers <philippe dot waroquiers at skynet dot be>]

The commands 'info [functions|variables|types]|rbreak' work
on the global program, not only in the current frame.
So in in mixed languages program, these commands examine and print
entities defined in different languages.

Now, GDB uses the current language to print all the results of
these commands, which is somewhat surprising.

For example, when the current frame is in Ada,
info function gethostbyname gives:
  File ../nss/getXXbyYY.c:
  87:	function gethostbyname (a1: access char) return access hostent;

This patch series ensures that these commands respect the 'set language auto'
setup, to print the results in the language used to define the printed
entities.