Do not enable asynchronous cancellation in system. Fixes bug 14782.

We needlessly enabled thread cancellation before it was necessary. As
only call that needs to be guarded is waitpid which is cancellation
point we could remove cancellation altogether.

NEWS

@@ -12,20 +12,20 @@ Version 2.19
   156, 387, 431, 762, 832, 926, 2801, 4772, 6786, 6787, 6807, 6810, 7003,
   9721, 9954, 10253, 10278, 11087, 11157, 11214, 12100, 12486, 12986,
   13028, 13982, 13985, 14029, 14032, 14120, 14143, 14155, 14286, 14547,
-  14699, 14752, 14876, 14910, 15004, 15048, 15073, 15089, 15128, 15218,
-  15268, 15277, 15308, 15362, 15374, 15400, 15425, 15427, 15483, 15522,
-  15531, 15532, 15593, 15601, 15608, 15609, 15610, 15632, 15640, 15670,
-  15672, 15680, 15681, 15723, 15734, 15735, 15736, 15748, 15749, 15754,
-  15760, 15763, 15764, 15797, 15799, 15825, 15843, 15844, 15846, 15847,
-  15849, 15850, 15855, 15856, 15857, 15859, 15867, 15886, 15887, 15890,
-  15892, 15893, 15895, 15897, 15901, 15905, 15909, 15915, 15917, 15919,
-  15921, 15923, 15939, 15941, 15948, 15963, 15966, 15985, 15988, 15997,
-  16032, 16034, 16036, 16037, 16038, 16041, 16055, 16071, 16072, 16074,
-  16077, 16078, 16103, 16112, 16133, 16143, 16144, 16146, 16150, 16151,
-  16153, 16167, 16172, 16195, 16214, 16245, 16271, 16274, 16283, 16289,
-  16293, 16314, 16316, 16330, 16337, 16338, 16356, 16365, 16366, 16369,
-  16372, 16375, 16379, 16384, 16385, 16386, 16387, 16390, 16394, 16400,
-  16407, 16408, 16414.
+  14699, 14752, 14782, 14876, 14910, 15004, 15048, 15073, 15089, 15128,
+  15218, 15268, 15277, 15308, 15362, 15374, 15400, 15425, 15427, 15483,
+  15522, 15531, 15532, 15593, 15601, 15608, 15609, 15610, 15632, 15640,
+  15670, 15672, 15680, 15681, 15723, 15734, 15735, 15736, 15748, 15749,
+  15754, 15760, 15763, 15764, 15797, 15799, 15825, 15843, 15844, 15846,
+  15847, 15849, 15850, 15855, 15856, 15857, 15859, 15867, 15886, 15887,
+  15890, 15892, 15893, 15895, 15897, 15901, 15905, 15909, 15915, 15917,
+  15919, 15921, 15923, 15939, 15941, 15948, 15963, 15966, 15985, 15988,
+  15997, 16032, 16034, 16036, 16037, 16038, 16041, 16055, 16071, 16072,
+  16074, 16077, 16078, 16103, 16112, 16133, 16143, 16144, 16146, 16150,
+  16151, 16153, 16167, 16172, 16195, 16214, 16245, 16271, 16274, 16283,
+  16289, 16293, 16314, 16316, 16330, 16337, 16338, 16356, 16365, 16366,
+  16369, 16372, 16375, 16379, 16384, 16385, 16386, 16387, 16390, 16394,
+  16400, 16407, 16408, 16414.
 
 * Slovenian translations for glibc messages have been contributed by the
   Translation Project's Slovenian team of translators.

sysdeps/posix/system.c

@@ -181,15 +181,6 @@ __libc_system (const char *line)
        not be available after a chroot(), for example.  */
     return do_system ("exit 0") == 0;
 
-  if (SINGLE_THREAD_P)
-    return do_system (line);
-
-  int oldtype = LIBC_CANCEL_ASYNC ();
-
-  int result = do_system (line);
-
-  LIBC_CANCEL_RESET (oldtype);
-
-  return result;
+  return do_system (line);
 }
 weak_alias (__libc_system, system)