Tweak robust mutex detection for glibc

libraries/liblmdb/mdb.c

@@ -252,7 +252,9 @@ union semun {
 #define MDB_OWNERDEAD	EOWNERDEAD	/**< #LOCK_MUTEX0() result if dead owner */
 #endif
 
-
+#ifdef __GLIBC__
+#define	GLIBC_VER	((__GLIBC__ << 16 )| __GLIBC_MINOR__)
+#endif
 /** Some platforms define the EOWNERDEAD error code
  * even though they don't support Robust Mutexes.
  * Compile with -DMDB_USE_ROBUST=0, or use some other
@@ -262,12 +264,19 @@ union semun {
  * either.)
  */
 #ifndef MDB_USE_ROBUST
-/* Android currently lacks Robust Mutex support */
+/* Android currently lacks Robust Mutex support. So does glibc < 2.4. */
-#if defined(ANDROID) && defined(MDB_USE_POSIX_MUTEX) && !defined(MDB_USE_ROBUST)
+# if defined(MDB_USE_POSIX_MUTEX) && (defined(ANDROID) || \
-#define MDB_USE_ROBUST	0
+	(defined(__GLIBC__) && GLIBC_VER < 0x020004))
-#else
+#  define MDB_USE_ROBUST	0
-#define MDB_USE_ROBUST	1
+# else
-#endif
+#  define MDB_USE_ROBUST	1
+/* glibc < 2.10 only provided _np API */
+#  if defined(__GLIBC__) && GLIBC_VER < 0x02000a
+#   define PTHREAD_MUTEX_ROBUST	PTHREAD_MUTEX_ROBUST_NP
+#   define pthread_mutexattr_setrobust(attr, flag)	pthread_mutexattr_setrobust_np(attr, flag)
+#   define pthread_mutex_consistent(mutex)	pthread_mutex_consistent_np(mutex)
+#  endif
+# endif
 #endif /* MDB_USE_ROBUST */
 
 #if defined(MDB_OWNERDEAD) && MDB_USE_ROBUST