fix crash when XOpenIM returns NULL

for example when IME variables are set, but the program is not started (yet).

dmenu.c

@@ -664,8 +664,17 @@ setup(void)
 	                    CWOverrideRedirect | CWBackPixel | CWEventMask, &swa);
 	XSetClassHint(dpy, win, &ch);
 
-	/* open input methods */
+
-	xim = XOpenIM(dpy, NULL, NULL, NULL);
+	/* input methods */
+	if ((xim = XOpenIM(dpy, NULL, NULL, NULL)) == NULL) {
+		XSetLocaleModifiers("@im=local");
+		if ((xim = XOpenIM(dpy, NULL, NULL, NULL)) == NULL) {
+			XSetLocaleModifiers("@im=");
+			if ((xim = XOpenIM(dpy, NULL, NULL, NULL)) == NULL)
+				die("XOpenIM failed. Could not open input device.\n");
+		}
+	}
+
 	xic = XCreateIC(xim, XNInputStyle, XIMPreeditNothing | XIMStatusNothing,
 	                XNClientWindow, win, XNFocusWindow, win, NULL);