Let breakpad build with -Wall on OS X and Linux.

src/common/linux/synth_elf.cc

 #include "common/linux/synth_elf.h"
 
 #include <assert.h>
 #include <elf.h>
 #include <stdio.h>
 #include <string.h>
 
 #include "common/linux/elf_gnu_compat.h"
 #include "common/using_std_string.h"
 
@@ skipping 195 matching lines @@
   program_count_label_ = program_count_;
 
   // Section header table starts here.
   Mark(&section_header_label_);
   Append(section_header_table_);
 }
 
 SymbolTable::SymbolTable(Endianness endianness,
                          size_t addr_size,
                          StringTable& table) : Section(endianness),
-                                               addr_size_(addr_size),
                                                table_(table) {
+#ifndef NDEBUG
+  addr_size_ = addr_size;
+#endif
   assert(addr_size_ == 4 || addr_size_ == 8);
 }
 
 void SymbolTable::AddSymbol(const string& name, uint32_t value,
                             uint32_t size, unsigned info, uint16_t shndx) {
   assert(addr_size_ == 4);
   D32(table_.Add(name));
   D32(value);
   D32(size);
   D8(info);
@@ skipping 24 matching lines @@
   Append(reinterpret_cast<const uint8_t*>(&note_header),
          sizeof(note_header));
   AppendCString(name);
   Align(4);
   Append(desc_bytes, desc_size);
   Align(4);
 }
 
 }  // namespace synth_elf
 }  // namespace google_breakpad