gdb.threads/linux-dp.exp test nit

[Roland McGrath <roland@redhat.com>]

The test suite will produce:

 FAIL: gdb.threads/linux-dp.exp: first thread-specific breakpoint hit

if you have debugging information for libpthread available.  That is:

    gdb_test "where" "print_philosopher.*philosopher.* from .*libpthread.*" \
	    "first thread-specific breakpoint hit"

It expects the backtrace to say "something () from libpthread.so.0" for the
frames indicating the callers in libpthread of print_philosopher.  But my
backtrace looks like this:

#0  print_philosopher (n=3, left=33 '!', right=33 '!') at /home/roland/BUILD/gdb
+dejagnu-5.3.90_20030710/gdb/testsuite/gdb.threads/linux-dp.c:105
#1  0x08048aa3 in philosopher (data=0x804a094) at /home/roland/BUILD/gdb+dejagnu
-5.3.90_20030710/gdb/testsuite/gdb.threads/linux-dp.c:148
#2  0x4001c9ea in start_thread (arg=0x21) at pthread_create.c:264
#3  0x40136247 in clone () from /lib/tls/libc.so.6


The crucial line is #2, where it has source info instead of "from
libpthread".  The assumption that the backtrace will look either of these
ways is bogus anyway.  The threads implementation could well produce a
backtrace that didn't show a recognizable frame before `philosopher'.  If
the intent of this test predicate is to make sure it's in the right thread,
it really ought to be looking at the N argument to print_philosopher in the
backtrace.


Thanks,
Roland