🧪 [makefile] pass CC_OPTS variable as define string

[stnolting]

Pass the makefile's CC_OPTS variable, which contains all relevant GCC flags and switches, as "define" string to the application:

# Actual flags passed to the compiler
CC_FLAGS = $(CC_OPTS)

# Export compiler flags as define string
CC_FLAGS += -DCC_OPTS="\"$(CC_OPTS)\""

Application software can use this "define" to print the actual GCC configuration that was used to compile the code:

neorv32_uart0_printf("%s\n", CC_OPTS);