Write release id if rspamd is built from hg.

CMakeLists.txt

 SET(RSPAMD_VERSION_MINOR 3)
 SET(RSPAMD_VERSION_PATCH 3)
 
+
 SET(RSPAMD_VERSION         "${RSPAMD_VERSION_MAJOR}.${RSPAMD_VERSION_MINOR}.${RSPAMD_VERSION_PATCH}")
 SET(RSPAMD_MASTER_SITE_URL "http://bitbucket.org/vstakhov/rspamd")
 SET(RSPAMD_USER "nobody")
     SET(DESTDIR $ENV{DESTDIR})
 ENDIF(NOT DESTDIR)
 
+# Try to detect tip version from hg
+SET(ID "unknown")
+FIND_PROGRAM(HG "hg")
+
+IF(HG)
+    EXECUTE_PROCESS(COMMAND ${HG} "id" OUTPUT_VARIABLE HG_ID)   
+    IF(HG_ID)
+        STRING(REGEX MATCH ^[0-9a-z]+ ID "${HG_ID}")
+    ENDIF(HG_ID)
+ELSE(HG)
+# Now check .hg_archival.txt
+    FIND_FILE(HG_ARCH ".hg_archival.txt" "${CMAKE_CURRENT_SOURCE_DIR}")   
+    IF(HG_ARCH)
+        FILE(READ ${HG_ARCH} HG_ID)
+        IF(HG_ID)
+            STRING(REGEX MATCH "node: [0-9a-z]+" _tmp "${HG_ID}")
+            STRING(SUBSTRING "${_tmp}" 6 12 ID)
+        ENDIF(HG_ID)
+    ENDIF(HG_ARCH)
+ENDIF(HG)
+ 
+
 ################################ SOURCES SECTION ###########################
 
 SET(RSPAMDSRC	src/modules.c

config.h.in

 #cmakedefine HAVE_CLOCK_GETTIME  1
 
 #define RVERSION          "${RSPAMD_VERSION}"
+#define RID               "${ID}"
 #define RSPAMD_MASTER_SITE_URL "${RSPAMD_MASTER_SITE_URL}"
 
 #define MODULES_NUM        ${RSPAMD_MODULES_NUM}

src/main.c

 	GOptionContext                 *context;
 
 	context = g_option_context_new ("- run rspamd daemon");
-	g_option_context_set_summary (context, "Summary:\n  Rspamd daemon version " RVERSION);
+	g_option_context_set_summary (context, "Summary:\n  Rspamd daemon version " RVERSION "\n  Release id: " RID);
 	g_option_context_add_main_entries (context, entries, NULL);
 	if (!g_option_context_parse (context, &argc, &argv, &error)) {
 		fprintf (stderr, "option parsing failed: %s\n", error->message);
 
 	config_logger (rspamd, TRUE);
 
-	msg_info ("rspamd " RVERSION " is starting");
+	msg_info ("rspamd " RVERSION " is starting, build id: " RID);
 	rspamd->cfg->cfg_name = memory_pool_strdup (rspamd->cfg->cfg_pool, rspamd->cfg->cfg_name);
 
 	if (!rspamd->cfg->no_fork && daemon (0, 0) == -1) {