Fix the detection of the audit library and header file.

configure.in

@@ -218,7 +218,7 @@ AC_ARG_ENABLE(man,
 
 AC_ARG_WITH(audit, 
 	[AC_HELP_STRING([--with-audit], [use auditing support @<:@default=yes if found@:>@])],
-	[with_audit=$withval], [with_audit=yes])
+	[with_audit=$withval], [with_audit=maybe])
 AC_ARG_WITH(libpam,
 	[AC_HELP_STRING([--with-libpam], [use libpam for PAM support @<:@default=yes if found@:>@])],
 	[with_libpam=$withval], [with_libpam=yes])
@@ -275,12 +275,25 @@ AC_CHECK_LIB(crypt, crypt, [LIBCRYPT=-lcrypt],
 	[AC_MSG_ERROR([crypt() not found])])
 
 AC_SUBST(LIBAUDIT)
-if test "$with_audit" = "yes"; then
+if test "$with_audit" != "no"; then
 	AC_CHECK_HEADER(libaudit.h, [audit_header="yes"], [audit_header="no"])
-	if test "$audit_header" = "yes"; then
+	if test "$audit_header$with_audit" = "noyes" ; then
+		AC_MSG_ERROR([libaudit.h is missing])
+	elif test "$audit_header" = "yes"; then
 		AC_CHECK_LIB(audit, audit_log_acct_message,
-			[AC_DEFINE(WITH_AUDIT, 1, [Define if you want to enable Audit messages])
-			LIBAUDIT="-laudit"])
+		             [audit_lib="yes"], [audit_lib="no"])
+		if test "$audit_lib$with_audit" = "noyes" ; then
+			AC_MSG_ERROR([libaudit not found])
+		elif test "$audit_lib" = "no" ; then
+			with_audit="no"
+		else
+			AC_DEFINE(WITH_AUDIT, 1,
+			          [Define if you want to enable Audit messages])
+			LIBAUDIT="-laudit"
+			with_audit="yes"
+		fi
+	else
+		with_audit="no"
 	fi
 fi