Build fail on GNU/Linux distros (Fedora) due to missing strnstr() function

[n7ekb]

cc -g -O -Wall -Werror -DVERSION='"1.1.255"' -I/usr/include/libusb-1.0 -c -o radio.o radio.c
radio.c: In function ‘radio_validate_config’:
radio.c:322:9: error: implicit declaration of function ‘strnstr’; did you mean ‘strstr’? [-Werror=implicit-function-declaration]
322 | if (strnstr(line, "Radio:", strlen(line))) {
| ^~~~~~~
| strstr
cc1: all warnings being treated as errors
make: *** [: radio.o] Error 1

[nathanielc]

I had this same issue and replaced strnstr with strstr removing the length parameter. The strnstr function is FreeUSB specific so this change made sense to me.