* xm-sun3os4.h, xm-sun4os4.h: Enable HAVE_MMAP.

* xm-sun3os4.h, xm-sun4os4.h:  Enable HAVE_MMAP.

* minsyms.c (install_minimal_symbols):  Add bunches to any
existing minsyms in the objfile.  Avoid extra mallocation
by working directly in the obstack.  Remove ignored `mainline' parm.
* coffread.c, dbxread.c, elfread.c, mipsread.c, solib.c, symtab.h,
xcoffread.c:  Change all callers.
* FIXME:  We should be able to eliminate MAINLINE from all the
symbol readers now, with a small bit of work.

* valops.c, value.h:  Lint.
* remote-vx.c:  Add missing break; statement.  Bugfix by
Michael Sclafani, <sclafani@src.dec.com>.