thread/Util: no ioprio_set() on Android due to seccomp/SIGSYS

NEWS

@@ -6,6 +6,7 @@ ver 0.20.15 (not yet released)
   - fix crash when restoring mounts with incompatible database plugin
 * Android
   - build without Ant
+  - fix for SIGSYS crash
 
 ver 0.20.14 (2018/01/01)
 * database

src/thread/Util.cxx

@@ -38,7 +38,7 @@
 #include <windows.h>
 #endif
 
-#ifdef __linux__
+#if defined(__linux__) && !defined(ANDROID)
 
 static int
 ioprio_set(int which, int who, int ioprio)
@@ -69,7 +69,11 @@ SetThreadIdlePriority()
 	sched_setscheduler(0, SCHED_IDLE, &sched_param);
 #endif
 
+#ifndef ANDROID
+	/* this system call is forbidden via seccomp on Android 8 and
+	   leads to crash (SIGSYS) */
 	ioprio_set_idle();
+#endif
 
 #elif defined(_WIN32)
 	SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_IDLE);