diff --git a/libc/bionic/malloc_debug_common.cpp b/libc/bionic/malloc_debug_common.cpp
index 248a2db..a05a5ef 100644
--- a/libc/bionic/malloc_debug_common.cpp
+++ b/libc/bionic/malloc_debug_common.cpp
@@ -256,7 +256,7 @@
     dlmalloc, dlfree, dlcalloc, dlrealloc, dlmemalign
 };
 
-extern char* __progname;
+extern const char* __progname;
 
 /* Handle to shared library where actual memory allocation is implemented.
  * This library is loaded and memory allocation calls are redirected there