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

src/client/mac/handler/dynamic_images.cc

Index: src/client/mac/handler/dynamic_images.cc
diff --git a/src/client/mac/handler/dynamic_images.cc b/src/client/mac/handler/dynamic_images.cc
index 3dc4f3b463dcf5232df02fa8a8c42cf491cf5dd4..cdba6df4acfbb1ce5695004e2b142ed53e47ca4a 100644
--- a/src/client/mac/handler/dynamic_images.cc
+++ b/src/client/mac/handler/dynamic_images.cc
@@ -364,7 +364,7 @@ static uint64_t LookupSymbol(const char* symbol_name,
   return list.n_value;
 }
 
-#if TARGET_OS_IPHONE
+#if TARGET_OS_IPHONE || MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_6
 static bool HasTaskDyldInfo() {
   return true;
 }
@@ -381,13 +381,9 @@ static SInt32 GetOSVersion() {
 }
 
 static bool HasTaskDyldInfo() {
-#if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_6
-  return true;
-#else
   return GetOSVersion() >= 0x1060;
-#endif
 }
-#endif  // TARGET_OS_IPHONE
+#endif  // TARGET_OS_IPHONE || MAC_OS_X_VERSION_MIN_REQUIRED >= 10_6
 
 uint64_t DynamicImages::GetDyldAllImageInfosPointer() {
   if (HasTaskDyldInfo()) {