If using WIFI_INIT_CONFIG_DEFAULT, error message will point out lack
of WiFi. Otherwise linker errors on WiFi symbols should help give a
clue as to what is broken.
Piggy-backs on changes in !420, ref github #230#237
- ROM function uart_tx_wait_idle may have a bug which causes the function to return before the final character is fully transmitted.
This replaces uart_tx_wait_idle declaration with a static inline definition which fixes the issue.
- Also replaces the use of uart_tx_flush with uart_tx_wait_idle in esp_restart, to remove garbage in console output on restart.
- rtc_printf is temporary replaced with a no-op, pending a new release of librtc.a. Current release assumes that UART0 is used for output,
and switches UART0 baud rate while doing frequency changes and printing some log output. This doesn’t work if a different UART is used for output.
