Eliminate build warnings in base/ for Android x64

base/debug/proc_maps_linux.cc

Index: base/debug/proc_maps_linux.cc
===================================================================
--- base/debug/proc_maps_linux.cc	(revision 254431)
+++ base/debug/proc_maps_linux.cc	(working copy)
@@ -18,8 +18,12 @@
 // is incompatible with Bionic's stdint.h defining uintptr_t as a unsigned int:

[Mark Mentovai, 2014/03/03 14:25:35]

What does Bionic’s inttypes.h define PRI/SCNxPTR as in __LP64__, and what does
stdint.h define uintptr_t as?

At the very least, the comment is incorrect. But it’s also quite possible that
you don’t need this new __LP64__ case inside the #ifdef, and can just put
!defined(__LP64__) on line 16.

 // https://code.google.com/p/android/issues/detail?id=57218
 #undef SCNxPTR
+#ifdef __LP64__
+#define SCNxPTR "lx"
+#else
 #define SCNxPTR "x"
 #endif
+#endif
 
 namespace base {
 namespace debug {