Functions only called by DumpFreeSpace need to be conditionally compiled.

src/client/linux/microdump_writer/microdump_writer.cc

 // Copyright (c) 2014, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
@@ skipping 44 matching lines @@
 using google_breakpad::LinuxPtraceDumper;
 using google_breakpad::MappingInfo;
 using google_breakpad::MappingList;
 using google_breakpad::MicrodumpExtraInfo;
 using google_breakpad::RawContextCPU;
 using google_breakpad::ThreadInfo;
 using google_breakpad::UContextReader;
 
 const size_t kLineBufferSize = 2048;
 
+#if !defined(__LP64__)
+// The following are only used by DumpFreeSpace, so need to be compiled
+// in conditionally in the same way.
+
 template <typename Dst, typename Src>
 Dst saturated_cast(Src src) {
   if (src >= std::numeric_limits<Dst>::max())
     return std::numeric_limits<Dst>::max();
   if (src <= std::numeric_limits<Dst>::min())
     return std::numeric_limits<Dst>::min();
   return static_cast<Dst>(src);
 }
 
 int Log2Floor(uint64_t n) {
@@ skipping 40 matching lines @@
   size_t best = invalid;
   for (size_t next = 0; next < mappings.size(); ++next) {
     if (MappingLessThan(mappings[curr], mappings[next]) &&
         (best == invalid || MappingLessThan(mappings[next], mappings[best]))) {
       best = next;
     }
   }
   return best;
 }
 
+#endif  // !__LP64__
+
 class MicrodumpWriter {
  public:
   MicrodumpWriter(const ExceptionHandler::CrashContext* context,
                   const MappingList& mappings,
                   const MicrodumpExtraInfo& microdump_extra_info,
                   LinuxDumper* dumper)
       : ucontext_(context ? &context->context : NULL),
 #if !defined(__ARM_EABI__) && !defined(__mips__)
         float_state_(context ? &context->float_state : NULL),
 #endif
@@ skipping 449 matching lines @@
     dumper.set_crash_signal(context->siginfo.si_signo);
     dumper.set_crash_thread(context->tid);
   }
   MicrodumpWriter writer(context, mappings, microdump_extra_info, &dumper);
   if (!writer.Init())
     return false;
   return writer.Dump();
 }
 
 }  // namespace google_breakpad