Use -O not -O3: reduces ccan/tdb test time from 24 to 18 seconds.
[ccan] / ccan / crc /
drwxr-xr-x   ..
-rw-r--r-- 977 _info
-rw-r--r-- 11322 crc.c
-rw-r--r-- 2888 crc.h
drwxr-xr-x - test