MINOR: http-htx: Support different methods to look for header names

It is now possible to use different matching methods to look for header names in
an HTTP message:

 * The exact match. It is the default method. http_find_header() uses this
   method. http_find_str_header() is an alias.

 * The prefix match. It evals the header names starting by a prefix.
   http_find_pfx_header() must be called to use this method.

 * The suffix match. It evals the header names ending by a suffix.
   http_find_sfx_header() must be called to use this method.

 * The substring match. It evals the header names containing a string.
   http_find_sub_header() must be called to use this method.

 * The regex match. It evals the header names matching a regular expression.
   http_match_header() must be called to use this method.
diff --git a/include/proto/http_htx.h b/include/proto/http_htx.h
index 99d56b4..9a70ca5 100644
--- a/include/proto/http_htx.h
+++ b/include/proto/http_htx.h
@@ -25,6 +25,7 @@
 
 #include <common/buf.h>
 #include <common/ist.h>
+#include <common/regex.h>
 
 #include <types/http_htx.h>
 
@@ -34,6 +35,11 @@
 struct htx_sl *http_get_stline(struct htx *htx);
 size_t http_get_hdrs_size(struct htx *htx);
 int http_find_header(const struct htx *htx, const struct ist name, struct http_hdr_ctx *ctx, int full);
+int http_find_str_header(const struct htx *htx, const struct ist name, struct http_hdr_ctx *ctx, int full);
+int http_find_pfx_header(const struct htx *htx, const struct ist prefix, struct http_hdr_ctx *ctx, int full);
+int http_find_sfx_header(const struct htx *htx, const struct ist suffix, struct http_hdr_ctx *ctx, int full);
+int http_find_sub_header(const struct htx *htx, const struct ist sub, struct http_hdr_ctx *ctx, int full);
+int http_match_header(const struct htx *htx, const struct my_regex *re, struct http_hdr_ctx *ctx, int full);
 int http_add_header(struct htx *htx, const struct ist n, const struct ist v);
 int http_replace_stline(struct htx *htx, const struct ist p1, const struct ist p2, const struct ist p3);
 int http_replace_req_meth(struct htx *htx, const struct ist meth);