Index: lib/profile/GCDAProfiling.c
===================================================================
--- lib/profile/GCDAProfiling.c
+++ lib/profile/GCDAProfiling.c
@@ -79,7 +79,7 @@
  * Buffer that we write things into.
  */
 #define WRITE_BUFFER_SIZE (128 * 1024)
-static char *write_buffer = NULL;
+static unsigned char *write_buffer = NULL;
 static uint64_t cur_buffer_size = 0;
 static uint64_t cur_pos = 0;
 static uint64_t file_size = 0;