Code cleanup mostly

Added a new compiler.h file courtesy of Bertrand Petit for some declaration macros.
Code cleanup & refactor.
Clang static analyzer pass, no error.

Added a FreeBSD 9+ PAM file & updated config.{sub,guess}

Minor update:

• Added a FreeBSD 9.0 and later PAM configuration file
• Update to 2014/11/4 versions for GNU utilities config.guess and config.sub.

3.0.4: Support for %group syntax, secure memzero().

Maintenance release to add a more secure way to clear memory blocks (following a blog post by Colin Percival.

Added the %group syntax in addition to the currently available @group to be closer to sudo(8) syntax.

3.0.3

Minor release to help porting to the new way of using "staged" directory for the FreeBSD ports.

Please also check the other two binaires on either https://bitbucket.org/keltia/calife/downloads/ or http://assets.keltia.net/calife/ (gibhub seems to have issues with uploading the .tar.gz and .tar.xz files...)

Calife 3.0.2 (RC)

Some cleaning done in auth.c to remove unused variables (thanks to clang as always).
Tested on FreeBSD and MacOS X for the moment.

SHA256(calife-3.0.2.tar.bz2)= 757c3fa7ff9df318c86c1219e4cfb215a444c2eb5e44d5557579d27c278e340c
SHA256(calife-3.0.2.tar.gz)= 9eaec17db7032972356f128f9851049485eeb8baad557c304ead2602b85da524
SHA256(calife-3.0.2.tar.xz)= b8db8c5c8c28473521e5ee92ecfb04ac373f56436c8550281d15a59d2602a86e

Fingerprint file signed by my GPG key 0x8BE879B028731E1C