Use 64 bit buffer lengths.

This is pulled out of the Confuga branch where we want to able to hash large
files. This commit also changes the <hash>_file routines to use mmap if
possible.
Add helper macros for creating a stack buffer.
Add routines to duplicate a buffer.
Use buffer_dup.
organize headers
Use stdint.h types and ssize_t.

Note that it is not possible for pwrite64/pread64 to return a value larger than
ssize_t in 32 bit mode. So also using ssize_t for full_(pwrite64|pread64) is
okay.
Merge duplicate code into macro.
Merge remote-tracking branch 'ccl/pull/565/head'

* ccl/pull/565/head:
  Merge duplicate code into macro.
  Use stdint.h types and ssize_t.
  organize headers
Merge remote-tracking branch 'ccl/pull/562/head'

* ccl/pull/562/head:
  Use 64 bit buffer lengths.
Merge remote-tracking branch 'ccl/pull/564/head'

* ccl/pull/564/head:
  Use buffer_dup.
  Add routines to duplicate a buffer.
Merge remote-tracking branch 'ccl/pull/563/head'

* ccl/pull/563/head:
  Add helper macros for creating a stack buffer.
Remove required length from buffer_tostring.

o Adds new buffer_tolstring which matches the old function.
o buffer_tostring is now a macro calling buffer_tolstring.
Convert to new buffer_to*string behavior.

o When second parameter is NULL, use buffer_tostring.
o When second parameter is not NULL, change name to buffer_tolstring.
Update test case for buffer_to*string.
Merge pull request #574 from batrick/buffer-tostring

Buffer tostring
Redirect /var/run/nscd/socket to ENOENT to disable NSCD.

Name Service Cache Daemon (NSCD) is installed in CSE workstations for
passwd, group services, which does not check /etc/passwd and /etc/group.
parrot_identity_box is based on adding items into /etc/passwd and /etc/group.
Merge pull request #577 from hmeng-19/parrot_identity_box

Disable NSCD when using parrot_identity_box
remove unnecessary wrappers
Add a good PRNG (mersenne twister) for cctools.

NOTE: this is not a CSPRNG.
Includes some useful helper functions.
Replaces the old random_init.[ch]. srand is still seeded.
Reduce loop count to speedup test.