* configure.ac (NEED_GNUTLS_VERSION): New.
(HTTP_USE_GNUTLS, LIBGNUTLS_CFLAGS, LIBGNUTLS_LIBS): New ac_subst.
* common/http.h (http_session_t): New.
* common/http.c: Remove compatibility for gnutls < 3.0.
(http_session_s): New.
(cookie_s): Replace gnutls_session_t by http_session_t.
(tls_callback, tls_ca_certlist): New variables.
(my_socket_unref): Add preclose args.
(my_npth_read, my_npth_write): New.
(make_header_line): Fix bug using int* instead of char*.
(http_register_tls_callback): New.
(http_register_tls_ca): New.
(http_session_new): New.
(http_session_release): New.
(http_get_header_names): New.
(escape_data): Add hack to escape in forms mode.
(send_request) [HTTP_USE_GNUTLS]: Support SNI.
(send_request) [HTTP_USE_GNUTLS]: Fix use of make_header_line.
(send_gnutls_bye): New.
(cookie_close): Make use of preclose feature.
(http_verify_server_credentials): New.
(main) [TEST]: Remove test code.
* common/t-http.c: New.
* common/tls-ca.pem: New.
* common/Makefile.am (tls_sources): New. Move http code to here.
(libcommontls_a_SOURCES): New.
(libcommontlsnpth_a_SOURCES): New.
(EXTRA_DIST): Add tls-ca.pem
(module_maint_tests): Add t-http.
(t_http_SOURCES, t_http_CFLAGS, t_http_LDADD): New.
* dirmngr/Makefile.am (dirmngr_LDADD): Add libcommontlsnpth.