tcmalloc: fixed config_linux.h to build for arm targets.

third_party/tcmalloc/chromium/src/config_linux.h

 /* src/config.h.  Generated from config.h.in by configure.  */
 /* src/config.h.in.  Generated from configure.ac by autoheader.  */
 
 /* Define to 1 if compiler supports __builtin_stack_pointer */
 /* #undef HAVE_BUILTIN_STACK_POINTER */
 
 /* Define to 1 if you have the <conflict-signal.h> header file. */
 /* #undef HAVE_CONFLICT_SIGNAL_H */
 
 /* Define to 1 if you have the <cygwin/signal.h> header file. */
@@ skipping 195 matching lines @@
 /* Define to the one symbol short name of this package. */
 #define PACKAGE_TARNAME "google-perftools"
 
 /* Define to the home page for this package. */
 #undef PACKAGE_URL
 
 /* Define to the version of this package. */
 #define PACKAGE_VERSION "1.7"
 
 /* How to access the PC from a struct ucontext */
+/* TODO(asharif): configure.ac should be changed such that this define gets
+ * generated automatically. That change should go to upstream and then pulled
+ * back here. */
+#if defined(__arm__)
+#define PC_FROM_UCONTEXT uc_mcontext.arm_pc
+#else
 #define PC_FROM_UCONTEXT uc_mcontext.gregs[REG_RIP]
+#endif
 
 /* Always the empty-string on non-windows systems. On windows, should be
    "__declspec(dllexport)". This way, when we compile the dll, we export our
    functions/classes. It's safe to define this here because config.h is only
    used internally, to compile the DLL, and every DLL source file #includes
    "config.h" before anything else. */
 #define PERFTOOLS_DLL_DECL 
 
 /* printf format code for printing a size_t and ssize_t */
 #define PRIdS "zd"
@@ skipping 25 matching lines @@
 /* Define to `__inline__' or `__inline' if that's what the C compiler
    calls it, or to nothing if 'inline' is not supported under any name.  */
 #ifndef __cplusplus
 /* #undef inline */
 #endif
 
 
 #ifdef __MINGW32__
 #include "windows/mingw.h"
 #endif