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.
