fix prototype of dladdr

this breaks C++ source code in particular.

Change-Id: Ie06b5d31d23b5455e6950c470adc64dd5e7784df
diff --git a/linker/dlfcn.c b/linker/dlfcn.c
index a36b42c..7161455 100644
--- a/linker/dlfcn.c
+++ b/linker/dlfcn.c
@@ -124,7 +124,7 @@
     return 0;
 }
 
-int dladdr(void *addr, Dl_info *info)
+int dladdr(const void *addr, Dl_info *info)
 {
     int ret = 0;