MEDIUM: regex: replace all standard regex function by own functions

This patch remove all references of standard regex in haproxy. The last
remaining references are only in the regex.[ch] files.

In the file src/checks.c, the original function uses a "pmatch" array.
In fact this array is unused. This patch remove it.
diff --git a/include/types/proto_http.h b/include/types/proto_http.h
index ff196a0..affc231 100644
--- a/include/types/proto_http.h
+++ b/include/types/proto_http.h
@@ -419,7 +419,7 @@
 			char *name;            /* header name */
 			int name_len;          /* header name's length */
 			struct list fmt;       /* log-format compatible expression */
-			regex_t* re;           /* used by replace-header and replace-value */
+			struct my_regex re;    /* used by replace-header and replace-value */
 		} hdr_add;                     /* args used by "add-header" and "set-header" */
 		struct redirect_rule *redir;   /* redirect rule or "http-request redirect" */
 		int nice;                      /* nice value for HTTP_REQ_ACT_SET_NICE */
@@ -445,7 +445,7 @@
 			char *name;            /* header name */
 			int name_len;          /* header name's length */
 			struct list fmt;       /* log-format compatible expression */
-			regex_t* re;           /* used by replace-header and replace-value */
+			struct my_regex re;    /* used by replace-header and replace-value */
 		} hdr_add;                     /* args used by "add-header" and "set-header" */
 		int nice;                      /* nice value for HTTP_RES_ACT_SET_NICE */
 		int loglevel;                  /* log-level value for HTTP_RES_ACT_SET_LOGL */