Convert the project to use the GNU Build System (aka Autotools)

LICENSE was renamed COPYING because otherwise `autoreconf` complains loudly.
This is also the reason AUTHORS, INSTALL, and README were created.

Man pages were moved into src/pam_panic/man and src/pam_panic_pw/man.

Finally, certain variables are passed through the config.h file to the
module rather than as -D flags on the command-line.

src/pam_panic/Makefile.am

@@ -0,0 +1,13 @@
+SUBDIRS = man
+
+securelibdir = $(SECUREDIR)
+securelibexecdir = $(securelibdir)
+
+securelibexec_LTLIBRARIES = pam_panic.la
+pam_panic_la_SOURCES = \
+	pam_panic.c \
+	pam_panic_authdevice.c \
+	pam_panic_password.c \
+	pam_panic_reject.c
+pam_panic_la_LDFLAGS = -module -no-undefined -avoid-version
+pam_panic_la_LIBADD = -lpam -lcrypto