message: Don't make up names with double underscores
  They're reserved for use by the compiler, standard library, etc.
  Cr-Commit-Position: refs/heads/master@{#32038}
diff: #include <stdlib.h>
  #include <string.h>
  #include <features.h>
  -#ifndef __GLIBC_PREREQ
  -#define __GLIBC_PREREQ(a, b) 0
  +
  +#ifdef __GLIBC_PREREQ
  +#define WEBRTC_GLIBC_PREREQ(a, b) __GLIBC_PREREQ(a, b)
  +#else
  +#define WEBRTC_GLIBC_PREREQ(a, b) 0
  #endif
  -#if __GLIBC_PREREQ(2, 16)
  +
  +#if WEBRTC_GLIBC_PREREQ(2, 16)
  #include <sys/auxv.h>
  #else
  #include <fcntl.h>
  #include <errno.h>
  #include <link.h>
  #endif
  +
  #include "rtc_base/system/arch.h"
  #include "system_wrappers/include/cpu_features_wrapper.h"
  @@ -33,7 +38,7 @@ uint64_t WebRtc_GetCPUFeaturesARM(void) {
  int architecture = 0;
  unsigned long hwcap = 0;
  const char* platform = NULL;
  -#if __GLIBC_PREREQ(2, 16)
  +#if WEBRTC_GLIBC_PREREQ(2, 16)
  hwcap = getauxval(AT_HWCAP);
  platform = (const char*)getauxval(AT_PLATFORM);
  #else
  @@ -57,7 +62,7 @@ uint64_t WebRtc_GetCPUFeaturesARM(void) {
  }
  close(fd);
  }
  -#endif // __GLIBC_PREREQ(2,16)
  +#endif // WEBRTC_GLIBC_PREREQ(2, 16)
  #if defined(__aarch64__)
  architecture = 8;
  if ((hwcap & HWCAP_FP) != 0)
  