-p and --prefix=
diff --git a/src/os/unix/ngx_files.h b/src/os/unix/ngx_files.h
index 7d83b04..8608e17 100644
--- a/src/os/unix/ngx_files.h
+++ b/src/os/unix/ngx_files.h
@@ -158,7 +158,7 @@
 
 #define ngx_realpath(p, r)       realpath((char *) p, (char *) r)
 #define ngx_realpath_n           "realpath()"
-#define ngx_getcwd(buf, size)    (getcwd(buf, size) != NULL)
+#define ngx_getcwd(buf, size)    (getcwd((char *) buf, size) != NULL)
 #define ngx_getcwd_n             "getcwd()"
 #define ngx_path_separator(c)    ((c) == '/')