Add flag to disable start-up banner (#3026)

app/include/user_config.h

@@ -22,6 +22,26 @@
 //#define BIT_RATE_AUTOBAUD
 
 
+// At start-up firmware details like:
+//
+// NodeMCU 3.0.1.0
+//         branch:
+//         commit:
+//         release:
+//         release DTS:
+//         SSL: false
+//         build type: integer
+//         LFS: 0x0
+//         modules: file,gpio,net,node,rtctime,sntp,tmr,uart,wifi
+//  build 2020-01-27 17:39 powered by Lua 5.1.4 on SDK 3.0.2(824dc80)
+//
+// will be printed to serial console.  While it's mandatory for bug reports
+// and good for development, it may be unwanted for non-interactive serial
+// devices.
+
+//#define DISABLE_STARTUP_BANNER
+
+
 // Three separate build variants are now supported. The main difference is in the
 // processing of numeric data types.  If LUA_NUMBER_INTEGRAL is defined, then
 // all numeric calculations are done in integer, with divide being an integer

app/lua/lua.c

@@ -245,7 +245,9 @@ static int pmain (lua_State *L) {
 
   input_setup(LUA_MAXINPUT, get_prompt(L, 1));
   lua_input_string(" \n", 2);               /* queue CR to issue first prompt */
+#if !defined(DISABLE_STARTUP_BANNER)
   print_version(L);
+#endif
 
   /* and last of all, kick off application initialisation */
   if (init[0] == '@')