I'm having the following issue:

$ make
CC duktape_main.o
AR libmain.a
LD esp32-duktape.elf
C:/esp/proto/build/main\libmain.a(duktape_main.o):(.literal.app_main+0x28): undefined reference to `xPortGetFreeHeapSizeTagged'
C:/esp/proto/build/main\libmain.a(duktape_main.o): In function `app_main':
C ...