fixed EOL conversion on UTF-8 texts

* The old bug of saving gchar in gints, so teco_eol_reader_t::last_char could become negative.
* When converting from an UTF-8 text with CRLF linebreaks, we could have data loss and corruptions.
* On strings ending in UTF-8 characters, teco_eol_reader_t::offset would overflow, resulting
  in invalid reads and potentially insertion of data garbage.
  I observed this with G~ on Gtk.
* Test cased updated. Couldn't reproduce the bug with the test suite, though.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/eol.c b/src/eol.c
index 0063bbd..3439869 100644
--- a/src/eol.c
+++ b/src/eol.c
@@ -239,7 +239,7 @@ teco_eol_reader_convert(teco_eol_reader_t *ctx, gchar **ret, gsize *data_len, GE
 				else if (ctx->eol_style != SC_EOL_CR)
 					ctx->eol_style_inconsistent = TRUE;
 			}
-			ctx->last_char = buffer[i];
+			ctx->last_char = (guchar)buffer[i];
 			break;
 		}
 	}