Use getauxval() if available.

include/v8config.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8CONFIG_H_
 #define V8CONFIG_H_
 
 // Platform headers for feature detection below.
 #if defined(__ANDROID__)
 # include <sys/cdefs.h>
@@ skipping 102 matching lines @@
 #endif
 
 
 // -----------------------------------------------------------------------------
 // C library detection
 //
 //  V8_LIBC_MSVCRT  - MSVC libc
 //  V8_LIBC_BIONIC  - Bionic libc
 //  V8_LIBC_BSD     - BSD libc derivate
 //  V8_LIBC_GLIBC   - GNU C library
-//  V8_LIBC_UCLIBC  - uClibc

[Benedikt Meurer, 2014/10/22 06:15:07]

This was unused and crappy, so I removed that on the way.

 //
 // Note that testing for libc must be done using #if not #ifdef. For example,
 // to test for the GNU C library, use:
 //  #if V8_LIBC_GLIBC
 //   ...
 //  #endif
 
 #if defined (_MSC_VER)
 # define V8_LIBC_MSVCRT 1
 #elif defined(__BIONIC__)
 # define V8_LIBC_BIONIC 1
 # define V8_LIBC_BSD 1
-#elif defined(__UCLIBC__)
-# define V8_LIBC_UCLIBC 1
 #elif defined(__GLIBC__) || defined(__GNU_LIBRARY__)
 # define V8_LIBC_GLIBC 1
 #else
 # define V8_LIBC_BSD V8_OS_BSD
 #endif
 
 
 // -----------------------------------------------------------------------------
 // Compiler detection
 //
@@ skipping 261 matching lines @@
 # define V8_ALIGNOF(type) __alignof__(type)
 #else
 // Note that alignment of a type within a struct can be less than the
 // alignment of the type stand-alone (because of ancient ABIs), so this
 // should only be used as a last resort.
 namespace v8 { template <typename T> class AlignOfHelper { char c; T t; }; }
 # define V8_ALIGNOF(type) (sizeof(::v8::AlignOfHelper<type>) - sizeof(type))
 #endif
 
 #endif  // V8CONFIG_H_