Fix GNU strerror_r check for Android.

[danalbert]

Summary

Bionic didn't get a GNU style strerror_r until Android M. Until then
we unconditionally exposed the POSIX one. Expand the check to account
for this.

[srhines]

LGTM from the Android side.

[jlpeyton]

LGTM

runtime/src/kmp_i18n.cpp

#else // Non-Windows* OS: Linux* OS or OS X*
 
         /*
             There are 2 incompatible versions of strerror_r:
 
                 char * strerror_r( int, char *, size_t );  // GNU version
                 int    strerror_r( int, char *, size_t );  // XSI version
         */
 
-        #if defined(__GLIBC__) && defined(_GNU_SOURCE)
+        #if (defined(__GLIBC__) && defined(_GNU_SOURCE)) || \
+            (defined(__BIONIC__) && defined(_GNU_SOURCE) && \
+             __ANDROID_API__ >= __ANDROID_API_M__)
 
             // GNU version of strerror_r.
 
             char   buffer[ 2048 ];
             char * const err_msg = strerror_r( err, buffer, sizeof( buffer ) );
                 // Do not eliminate this assignment to temporary variable, otherwise compiler would
                 // not issue warning if strerror_r() returns `int' instead of expected `char *'.
             message = __kmp_str_format( "%s", err_msg );