fix prototype of dladdr

this breaks C++ source code in particular.

Change-Id: Ie06b5d31d23b5455e6950c470adc64dd5e7784df
diff --git a/linker/linker.c b/linker/linker.c
index 675b8b2..e0a8a18 100644
--- a/linker/linker.c
+++ b/linker/linker.c
@@ -546,7 +546,7 @@
     return NULL;
 }
 
-soinfo *find_containing_library(void *addr)
+soinfo *find_containing_library(const void *addr)
 {
     soinfo *si;
 
@@ -560,7 +560,7 @@
     return NULL;
 }
 
-Elf32_Sym *find_containing_symbol(void *addr, soinfo *si)
+Elf32_Sym *find_containing_symbol(const void *addr, soinfo *si)
 {
     unsigned int i;
     unsigned soaddr = (unsigned)addr - si->base;