* lib/gdb.exp (gdb_breakpoint): Add pending breakpoint
support.
* gdb.base/langs.exp: Fix test which attempts to create
breakpoint on non-existent function to handle new pending
support.
* gdb.base/shlib-call.exp: Use gdb_breakpoint to set
a breakpoint.
* gdb.base/pending.exp: New test.
* gdb.base/pending.c: New file.
* gdb.base/pendshr.c: Ditto.