diff --git a/includes.h b/includes.h
index 6738ca2..5b1fdea 100644
--- a/includes.h
+++ b/includes.h
@@ -91,9 +91,6 @@
 #ifdef HAVE_SYS_BITYPES_H
 # include <sys/bitypes.h> /* For u_intXX_t */
 #endif
-#ifdef HAVE_SYS_CDEFS_H
-# include <sys/cdefs.h> /* For __P() */
-#endif
 #ifdef HAVE_SYS_STAT_H
 # include <sys/stat.h> /* For S_* constants and macros */
 #endif
diff --git a/pam_get_pass.c b/pam_get_pass.c
index 2be11a8..7bfa901 100644
--- a/pam_get_pass.c
+++ b/pam_get_pass.c
@@ -23,9 +23,6 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
-
-#include <sys/cdefs.h>
-
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
diff --git a/pam_get_pass.h b/pam_get_pass.h
index 9c3dd76..3f69fb8 100644
--- a/pam_get_pass.h
+++ b/pam_get_pass.h
@@ -26,7 +26,11 @@
  *	$FreeBSD: src/lib/libpam/libpam/security/pam_mod_misc.h,v 1.10.4.1 2002/07/16 12:33:23 des Exp $
  */
 
-__BEGIN_DECLS
+#ifdef __cplusplus
+extern "C" {
+#endif
 int	pam_get_pass(pam_handle_t *, const char **, const char *, struct options *);
 int pam_conv_pass(pam_handle_t *, const char *, struct options *);
-__END_DECLS
+#ifdef __cplusplus
+}
+#endif
diff --git a/pam_option.h b/pam_option.h
index e866424..f288720 100644
--- a/pam_option.h
+++ b/pam_option.h
@@ -26,8 +26,6 @@
  * $Id: pam_option.h,v 1.1 2002/09/20 00:00:55 akorty Exp $
  */
 
-#include <sys/cdefs.h>
-
 /* Standard options */
 
 enum opt {
@@ -52,7 +50,11 @@ struct options {
 	} opt[PAM_MAX_OPTIONS];
 };
 
-__BEGIN_DECLS
+#ifdef __cplusplus
+extern "C" {
+#endif
 void	pam_std_option(struct options *, struct opttab *, int, const char **);
 int	pam_test_option(struct options *, enum opt, char **);
-__END_DECLS
+#ifdef __cplusplus
+}
+#endif
diff --git a/pam_ssh.c b/pam_ssh.c
index faccde4..a50d4db 100644
--- a/pam_ssh.c
+++ b/pam_ssh.c
@@ -41,7 +41,6 @@
 /* to get the asprintf() prototype from the glibc headers */
 #define _GNU_SOURCE
 
-#include <sys/cdefs.h>
 #include <sys/param.h>
 #include <sys/stat.h>
 #include <sys/types.h>
diff --git a/pam_std_option.c b/pam_std_option.c
index ed1013d..3d36bff 100644
--- a/pam_std_option.c
+++ b/pam_std_option.c
@@ -23,9 +23,6 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
-
-#include <sys/cdefs.h>
-
 #include <stdio.h>
 #include <string.h>
 #include <pam_appl.h>