gcc -std=c99 -O2 -funroll-all-loops `pcre-config --cflags` `pcre-config --libs` -lcrypto -o trip trip-regex.c
or if you don't have pcre and can't install it:
gcc -std=c99 -O2 -funroll-all-loops -lcrypto -o trip trip.c
you're probably better off using trip-regex.c instead of trip.c if you can. if you have to use trip.c, you should grab it again (i just made some minor changes), and if you still get an error about strcasestr not being defined, try compiling it with -DNO_STRCASESTR
.