1.9.0 build error with musl libc

[rofl0r]

./pcap-usb-linux.c: In function 'usb_findalldevs':
./pcap-usb-linux.c:264:19: error: 'PATH_MAX' undeclared (first use in this function)
  char usb_mon_dir[PATH_MAX];
                   ^~~~~~~~
./pcap-usb-linux.c:264:19: note: each undeclared identifier is reported only once for each function it appears in
./pcap-usb-linux.c: In function 'probe_devices':
./pcap-usb-linux.c:419:41: error: 'NAME_MAX' undeclared (first use in this function)
  char buf[sizeof("/dev/bus/usb/000/") + NAME_MAX];
                                         ^~~~~~~~

looks as if <limits.h> isn't included as it should

[guyharris]

Dup of pull request #735.