-Werror -Wall -Wstrict-prototypes -Wmissing-prototypes
-Wcast-qual -Wno-format
(if not already set). -Wno-format is necessary because of the few
bits of code in the tree that use NetBSD's special kernel printf()
formats, and because there are a few bits of code that try to use the 'q'
modifier to print int64_t's (but int64_t's are only 'long' on the
alpha, not 'long long').