MINOR: regex: Change the struct containing regex

This change permits to remove the typedef. The original regex structs
are set in haproxy's struct.
diff --git a/src/pattern.c b/src/pattern.c
index 6d7de52..3ac8f03 100644
--- a/src/pattern.c
+++ b/src/pattern.c
@@ -476,7 +476,7 @@
 /* Parse a regex. It is allocated. */
 int pat_parse_reg(const char **text, struct pattern *pattern, int *opaque, char **err)
 {
-	regex *preg;
+	struct my_regex *preg;
 
 	preg = calloc(1, sizeof(*preg));
 
diff --git a/src/regex.c b/src/regex.c
index a268996..7a76940 100644
--- a/src/regex.c
+++ b/src/regex.c
@@ -122,7 +122,7 @@
 	return NULL;
 }
 
-int regex_comp(const char *str, regex *regex, int cs, int cap, char **err)
+int regex_comp(const char *str, struct my_regex *regex, int cs, int cap, char **err)
 {
 #ifdef USE_PCRE_JIT
 	int flags = 0;
@@ -154,7 +154,7 @@
 	if (!cap)
 		flags |= REG_NOSUB;
 
-	if (regcomp(regex, str, flags) != 0) {
+	if (regcomp(&regex->regex, str, flags) != 0) {
 		memprintf(err, "regex '%s' is invalid", str);
 		return 0;
 	}