Google Breakpad Issue 417: Handle DWARF that omits function names.

This patch makes sure dump_syms behaves properly when presented with
malformed DWARF data that provides no name for a function. We print a
warning message to stderr, and subsitute "<name omitted>" for the empty
string, so that the "FUNC" record written to the symbol file for the
function is still well-formed. (We may have line number data covering the
function, so it would be a shame to omit the function altogether.)

Unit tests included.
a=jimblandy, r=ted.mielczarek


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@779 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/common/module.h

@@ -189,7 +189,7 @@ class Module {
   // Write is used.
   void SetLoadAddress(Address load_address);
 
-  // Add FUNCTION to the module.
+  // Add FUNCTION to the module. FUNCTION's name must not be empty.
   // This module owns all Function objects added with this function:
   // destroying the module destroys them as well.
   void AddFunction(Function *function);