cmake HAVE_SYS_BUFMOD_H examples

asset-group/5ghoul-5g-nr-attacks libs/libpcap/CMakeLists.txt :1261 

check_include_file(sys/bufmod.h HAVE_SYS_BUFMOD_H)

CTSRD-CHERI/cheribsd contrib/libpcap/CMakeLists.txt :1985 

check_include_file(sys/bufmod.h HAVE_SYS_BUFMOD_H)