diff -ru grep-2.5.orig/src/dfa.c grep-2.5/src/dfa.c
--- grep-2.5.orig/src/dfa.c	2001-09-26 09:57:55.000000000 -0700
+++ grep-2.5/src/dfa.c	2004-05-14 13:48:46.000000000 -0700
@@ -1052,12 +1052,14 @@
 			  setbit_case_fold (c, ccl);
 		      } else {
 			/* POSIX locales are painful - leave the decision to libc */
-			char expr[6] = { '[', c, '-', c2, ']', '\0' };
+			char expr[6];
 			regex_t re;
+			sprintf (expr, "[%c-%c]", c, c2);
 			if (regcomp (&re, expr, case_fold ? REG_ICASE : 0) == REG_NOERROR) {
 			  for (c = 0; c < NOTCHAR; ++c) {
-			    char buf[2] = { c, '\0' };
+			    char buf[2];
 			    regmatch_t mat;
+			    sprintf (buf, "%c", c);
 			    if (regexec (&re, buf, 1, &mat, 0) == REG_NOERROR
                                && mat.rm_so == 0 && mat.rm_eo == 1)
                               setbit_case_fold (c, ccl);