Apply two changes, systematically:

(1) Use PyErr_NewException("module.class", NULL, NULL) to create the
    exception object.

(2) Remove all calls to Py_FatalError(); instead, return or
    ignore the errors -- the import code now checks PyErr_Occurred()
    after calling a module's init function, so it's no longer a
    fatal error for the initialization to fail.

Also did some small cleanups, e.g. removed unnecessary test for
"already initialized" from initfpectl(), and unified
initposix()/initnt().

I haven't checked this very thoroughly, so while the changes are
pretty trivial -- beware of untested code!
diff --git a/Modules/dlmodule.c b/Modules/dlmodule.c
index d946658..9d7ce71 100644
--- a/Modules/dlmodule.c
+++ b/Modules/dlmodule.c
@@ -229,16 +229,18 @@
 	PyObject *m, *d, *x;
 
 	if (sizeof(int) != sizeof(long) ||
-	    sizeof(long) != sizeof(char *))
-		Py_FatalError(
+	    sizeof(long) != sizeof(char *)) {
+		Py_Err_SetStr(
  "module dl requires sizeof(int) == sizeof(long) == sizeof(char*)");
+		return;
+	}
 
 	/* Create the module and add the functions */
 	m = Py_InitModule("dl", dl_methods);
 
 	/* Add some symbolic constants to the module */
 	d = PyModule_GetDict(m);
-	Dlerror = x = PyString_FromString("dl.error");
+	Dlerror = x = PyErr_NewException("dl.error", NULL, NULL);
 	PyDict_SetItemString(d, "error", x);
 	x = PyInt_FromLong((long)RTLD_LAZY);
 	PyDict_SetItemString(d, "RTLD_LAZY", x);
@@ -246,8 +248,4 @@
 	x = PyInt_FromLong((long)RTLD_NOW);
 	PyDict_SetItemString(d, "RTLD_NOW", x);
 #endif
-
-	/* Check for errors */
-	if (PyErr_Occurred())
-		Py_FatalError("can't initialize module dl");
 }