added code to handle an empty regular expression in sed

qse/lib/cmn/tre-parse.c

@@ -1539,8 +1539,7 @@ parse_brace:
 					/* Escaped character. */
 					DPRINT(("tre_parse:     escaped: '%.*" STRF "'\n",
 					        REST(ctx->re - 1)));
-					result = tre_ast_new_literal(ctx->mem, *ctx->re, *ctx->re,
-					                             ctx->position);
+					result = tre_ast_new_literal(ctx->mem, *ctx->re, *ctx->re, ctx->position);
 					ctx->position++;
 					ctx->re++;
 				}

qse/lib/cmn/tre.h

@@ -91,7 +91,11 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #define tre_tolower(c)  QSE_TOLOWER(c)
 #define tre_toupper(c)  QSE_TOUPPER(c)
 
-typedef qse_char_t tre_char_t;
+#if defined(QSE_CHAR_IS_MCHAR) && (QSE_SIZEOF_MCHAR_T == QSE_SIZEOF_CHAR)
+	typedef unsigned char tre_char_t;
+#else
+	typedef qse_char_t tre_char_t;
+#endif
 typedef qse_cint_t tre_cint_t;
 
 #define size_t qse_size_t