gdbserver: rename source files to .cc

For the same reasons outlined in the previous patch, this patch renames
gdbserver source files to .cc.

I have moved the "-x c++" switch to only those rules that require it.

gdbserver/ChangeLog:

	* Makefile.in: Rename source files from .c to .cc.
	* %.c: Rename to %.cc.
	* configure.ac: Rename server.c to server.cc.
	* configure: Re-generate.
66 files changed