diff --git a/src/builddir.h b/src/builddir.h
index bc0c9e54..19825759 100644
--- a/src/builddir.h
+++ b/src/builddir.h
@@ -50,7 +50,7 @@ builddir_lookup(void)
 
 	/* readlink doesn't terminate the string and readlink says
 	   anything past sz is undefined */
-	execdir[++nread] = '\0';
+	execdir[nread] = '\0';
 
 	pathsep = strrchr(execdir, '/');
 	if (!pathsep)