Commandline define with string is in code replaced as identifier in stead of string

[Bascy]

Compiling the ESPmDNS library from arduinoe_esp32 an error occurs where ARDUINO_VARIANT is replaced by its command line definition.

The command line specifies: -DARDUINO_VARIANT="esp32"
the code is the following:

void MDNSResponder::enableArduino(uint16_t port, bool auth){ mdns_txt_item_t arduTxtData[4] = { {(char*)"board" ,(char*)ARDUINO_VARIANT}, {(char*)"tcp_check" ,(char*)"no"}, {(char*)"ssh_upload" ,(char*)"no"}, {(char*)"auth_upload" ,(char*)"no"} };

Because ARDUINO_VARIANT gets replaced with esp32 in stead of "esp32" the compilation fails with "unknown identifier esp32"

[jantje]

this is a duplicate of #1028
I would love to see esp to fix this by using the workaround I describe