squash w/ startup/shutdown? Cast nullptr to char* for execl.

plugins/auth/src/pam_password.cpp

@@ -109,7 +109,8 @@ namespace
         // The list of arguments must be terminated by a NULL pointer, and, since these are
         // variadic functions, this pointer must be cast (char *) NULL.
         const auto binary = irods::get_irods_sbin_directory() / "irodsPamAuthCheck";
-        execl(binary.c_str(), binary.c_str(), _username.c_str(), nullptr); // NOLINT(cppcoreguidelines-pro-type-vararg)
+        // NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg)
+        execl(binary.c_str(), binary.c_str(), _username.c_str(), static_cast<char*>(nullptr));
 
         irods::experimental::log::authentication::error("{}: Returning default value [SYS_FORK_ERROR]", __func__);
         THROW(SYS_FORK_ERROR, fmt::format("execl failed [errno:{}]", errno));