Bug#851371: libllvm3.9-dbg: lots of "Could not find DWO" and "in read in psymtab, but not in symtab" warnings

[Rebecca N. Palmer]

Control: severity -1 normal

Looks like this isn't just warnings - it also prevents breakpoints 
working in the affected files.

(Found while investigating #852746 - these are the only two places in 
LLVM with that error message, 
http://sources.debian.net/src/llvm-toolchain-3.9/1:3.9.1-3/lib/Support/CommandLine.cpp 
)

test1 at rnpalmer-laptop:/$ gdb clinfo
[...standard notice...]
Reading symbols from clinfo...(no debugging symbols found)...done.
(gdb) break lib/Support/CommandLine.cpp:255
No symbol table is loaded.  Use the "file" command.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (lib/Support/CommandLine.cpp:255) pending.
(gdb) break lib/Support/CommandLine.cpp:118
No symbol table is loaded.  Use the "file" command.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 2 (lib/Support/CommandLine.cpp:118) pending.
(gdb) break report_fatal_error
Function "report_fatal_error" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 3 (report_fatal_error) pending.
(gdb) run
Starting program: /usr/bin/clinfo
warning: Could not find DWO CU 
CMakeFiles/LLVMSupport.dir/CommandLine.cpp.dwo(0x2b6037c080c6d858) 
referenced by CU at offset 0x23c [in module 
/usr/lib/debug/.build-id/72/aac8d0efc8ef478117055f7d2ae20b7ea7e0d8.debug]
[...among many other similar messages...]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
warning: Could not find DWO CU 
CMakeFiles/LLVMSupport.dir/CommandLine.cpp.dwo(0x2b6037c080c6d858) 
referenced by CU at offset 0x23c [in module 
/usr/lib/debug/.build-id/72/aac8d0efc8ef478117055f7d2ae20b7ea7e0d8.debug]
[New Thread 0x7ffff0808700 (LWP 21181)]
[New Thread 0x7ffff0007700 (LWP 21182)]
[New Thread 0x7fffef806700 (LWP 21183)]
[New Thread 0x7fffef005700 (LWP 21184)]
[Thread 0x7fffef005700 (LWP 21184) exited]
[Thread 0x7fffef806700 (LWP 21183) exited]
[Thread 0x7ffff0007700 (LWP 21182) exited]
[Thread 0x7ffff0808700 (LWP 21181) exited]
: CommandLine Error: Option 'enable-value-profiling' registered more 
than once!
LLVM ERROR: inconsistency in registered CommandLine options
[Inferior 1 (process 21180) exited with code 01]
(gdb)