Make it possible for code to query the dynamic linker's default search path.

We're not going to have init(1) set LD_LIBRARY_PATH globally on 64-bit.
This patch makes it possible for libnativehelper to set LD_LIBRARY_PATH
in each Java VM (to support System.loadLibrary) without also hard-coding
the default search path there.

Change-Id: If13961fae976e06dd80d5ef522f31e8b7eb01154
diff --git a/libdl/libdl.c b/libdl/libdl.c
index 548364c..12ab39b 100644
--- a/libdl/libdl.c
+++ b/libdl/libdl.c
@@ -15,6 +15,8 @@
  */
 
 #include <dlfcn.h>
+#include <stdlib.h>
+
 /* These are stubs for functions that are actually defined
  * in the dynamic linker (dlfcn.c), and hijacked at runtime.
  */
@@ -24,6 +26,7 @@
 int dladdr(const void *addr, Dl_info *info) { return 0; }
 int dlclose(void *handle) { return 0; }
 
+void android_get_LD_LIBRARY_PATH(char* buffer, size_t buffer_size) { }
 void android_update_LD_LIBRARY_PATH(const char* ld_library_path) { }
 
 #if defined(__arm__)