Clean up internal libc logging.

We only need one logging API, and I prefer the one that does no
allocation and is thus safe to use in any context.

Also use O_CLOEXEC when opening the /dev/log files.

Move everything logging-related into one header file.

Change-Id: Ic1e3ea8e9b910dc29df351bff6c0aa4db26fbb58
diff --git a/libc/bionic/malloc_debug_leak.cpp b/libc/bionic/malloc_debug_leak.cpp
index 9e63a86..2db8a1f 100644
--- a/libc/bionic/malloc_debug_leak.cpp
+++ b/libc/bionic/malloc_debug_leak.cpp
@@ -47,7 +47,7 @@
 
 #include "debug_stacktrace.h"
 #include "dlmalloc.h"
-#include "logd.h"
+#include "libc_logging.h"
 #include "malloc_debug_common.h"
 #include "ScopedPthreadMutexLocker.h"