Rewrite syslog(3) to use Android logging.

Since we don't have syslogd on Android and you can't run one on a non-rooted
device, it's more useful if syslog output just goes to the regular Android
logging system.

Bug: 14292866
Change-Id: Icee7f088b97f88ccbdaf471b98cbac7f19f9210a
diff --git a/libc/bionic/libc_logging.cpp b/libc/bionic/libc_logging.cpp
index d0172ed..d6fa1db 100644
--- a/libc/bionic/libc_logging.cpp
+++ b/libc/bionic/libc_logging.cpp
@@ -378,6 +378,9 @@
         } else if (c == '%') {
             buffer[0] = '%';
             buffer[1] = '\0';
+        } else if (c == 'm') {
+            // syslog-like %m for strerror(errno).
+            str = strerror(errno);
         } else {
             __assert(__FILE__, __LINE__, "conversion specifier unsupported");
         }