lrzsz: Fix build with Jellybean 4.2

4.2 adds tcdrain(), so we can't define it here again

Change-Id: Ice561cf0fffdc4f02701531f5df41e132b4cfac8
Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>
diff --git a/rbsb.c b/rbsb.c
index be9a54f..c99e3c6 100644
--- a/rbsb.c
+++ b/rbsb.c
@@ -54,14 +54,23 @@
 # endif
 #endif
 
-/* Android lacks tcdrain() */
 #ifdef ANDROID
+/* Android prior to 4.2 lacks tcdrain().
+ * What we're doing here is fairly evil - but necessary since
+ * Bionic doesn't export any version identifier or the likes.
+ * We do know that 4.2 is the version introducing tcdrain() and
+ * also KLOG_CONSOLE_OFF -- completely unrelated, but something
+ * we can check for...
+ */
+#include <sys/klog.h>
+#ifndef KLOG_CONSOLE_OFF
 #include <sys/ioctl.h>
 static inline int tcdrain(int fd)
 {
 	return ioctl(fd, TCSBRK, 1);
 }
 #endif
+#endif
 
 #if defined(HOWMANY) && HOWMANY  > 255
 #ifndef NFGVMIN