use standard headers for siphash

ok tedu@

memcpy from the right place. at this point, the used variable is not
relevant. from Mark Karpilovskij.
ok millert

SipHash_Final() was assuming the digest was 64-bit aligned, resulting in
misaligned memory accesses with armv7 ramdisk -Os bsd.rd ping
ok florian millert

Wrap blowfish, sha*, md5, and rmd160 so that internal calls go direct

ok deraadt@

Use standard spelling for types, and rename local variable from "free".
No actual change, but makes it easier to reuse the code elsewhere.
Suggested by Andre Smagin

userland gets static on functions only used within a file.

ok tedu@

Move to the <limits.h> universe.
review by millert, binary checking process with doug, concept with guenther

add siphash from the kernel to libc