Handle bionic's strerror_r in an ABI-compatible way.

base/safe_strerror_posix.cc

 // Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#if defined(__ANDROID__)
+// Post-L versions of bionic define the GNU-specific strerror_r if _GNU_SOURCE
+// is defined, but the symbol is renamed to __gnu_strerror_r which only exists
+// on those later versions. To preserve ABI compatibility with older versions,
+// undefine _GNU_SOURCE and use the POSIX version.
+#undef _GNU_SOURCE
+#endif
+
 #include "build/build_config.h"
 #include "base/safe_strerror_posix.h"
 
 #include <errno.h>
 #include <stdio.h>
 #include <string.h>
 
-#define USE_HISTORICAL_STRERRO_R (defined(__GLIBC__) || defined(__BIONIC__) || \
-                                  defined(OS_NACL))
+#define USE_HISTORICAL_STRERRO_R (defined(__GLIBC__) || defined(OS_NACL))
 
 #if USE_HISTORICAL_STRERRO_R && defined(__GNUC__)
 // GCC will complain about the unused second wrap function unless we tell it
 // that we meant for them to be potentially unused, which is exactly what this
 // attribute is for.
 #define POSSIBLY_UNUSED __attribute__((unused))
 #else
 #define POSSIBLY_UNUSED
 #endif
 
@@ skipping 79 matching lines @@
   // static.
   wrap_posix_strerror_r(&strerror_r, err, buf, len);
 }
 
 std::string safe_strerror(int err) {
   const int buffer_size = 256;
   char buf[buffer_size];
   safe_strerror_r(err, buf, sizeof(buf));
   return std::string(buf);
 }