Fix a few impossible issues "found" by Coverity.

src/syncterm/bbslist.c

@@ -1094,13 +1094,13 @@ edit_name(char *itemname, struct bbslist **list, str_list_t inifile, bool edit_t
 		uifc.helpbuf = "`Directory Entry Name`\n\n"
 		    "Enter the name of the entry as it is to appear in the directory.";
 		if (itemname)
-			strcpy(tmp, itemname);
+			strlcpy(tmp, itemname, sizeof(tmp));
 		if (uifc.input(WIN_MID | WIN_SAV, 0, 0, "Name", tmp, LIST_NAME_MAX, K_EDIT) == -1)
 			return false;
 		check_exit(false);
 		if (quitting)
 			return false;
-		if ((edit_to_add || stricmp(tmp, itemname)) && list_name_check(list, tmp, NULL, false)) {
+		if ((edit_to_add || (itemname != NULL && stricmp(tmp, itemname))) && list_name_check(list, tmp, NULL, false)) {
 			uifc.helpbuf = "`Entry Name Already Exists`\n\n"
 			    "An entry with that name already exists in the directory.\n"
 			    "Please choose a unique name.\n";

src/syncterm/modem.c

@@ -271,6 +271,7 @@ modem_connect(struct bbslist *bbs)
 		/* Drain modem output buffer */
 		while (comReadByte(com, (uchar*)respbuf))
 			;
+		respbuf[0] = 0;
 
 		if (!bbs->hidepopups)
 			uifc.pop("Initializing...");

src/syncterm/term.c

@@ -3088,8 +3088,8 @@ read_jxl(const char *fn)
 	struct xpmapping *map = xpmap(fn, XPMAP_READ);
 	struct ciolib_pixels *pret = NULL;
 	uint8_t         *pbuf = NULL;
-	uintmax_t        width;
-	uintmax_t        height;
+	uintmax_t        width = 0;
+	uintmax_t        height = 0;
 
 	if (map == NULL)
 		return map;
@@ -3151,15 +3151,22 @@ read_jxl(const char *fn)
 #endif
 				break;
 			case JXL_DEC_NEED_IMAGE_OUT_BUFFER:
+				if (width == 0 || height == 0 || width >= 0x40000000 || hewight >= 0x40000000) {
+					done = true;
+					break;
+				}
 				if (Jxl.DecoderImageOutBufferSize(dec, &format, &sz) != JXL_DEC_SUCCESS) {
 					done = true;
 					break;
 				}
+				// This may break things, but Coverity wants it.
+				free(pbuf);
 				pbuf = malloc(sz);
 				if (pbuf == NULL) {
 					done = true;
 					break;
 				}
+				freepixels(pret);
 				pret = alloc_ciolib_pixels(width, height);
 				if (pret == NULL) {
 					done = true;