--- a/execinfo.c
+++ b/execinfo.c
@@ -52,6 +52,8 @@
     return nptr;
 }
 
+#pragma GCC visibility push(default)
+
 int
 backtrace(void **buffer, int size)
 {
@@ -78,7 +80,7 @@
     rval = malloc(clen);
     if (rval == NULL)
         return NULL;
-    (char **)cp = &(rval[size]);
+    cp = &(rval[size]);
     for (i = 0; i < size; i++) {
         if (dladdr(buffer[i], &info) != 0) {
             if (info.dli_sname == NULL)
@@ -158,3 +160,5 @@
         write(fd, buf, len - 1);
     }
 }
+
+#pragma GCC visibility pop