define appropriate feature test macros to get CBAUD from termios.h
diff --git a/src/termios/cfgetospeed.c b/src/termios/cfgetospeed.c
index 0ebc198..55fa6f5 100644
--- a/src/termios/cfgetospeed.c
+++ b/src/termios/cfgetospeed.c
@@ -1,3 +1,4 @@
+#define _BSD_SOURCE
 #include <termios.h>
 #include <sys/ioctl.h>
 
diff --git a/src/termios/cfsetospeed.c b/src/termios/cfsetospeed.c
index 80c790f..b571f62 100644
--- a/src/termios/cfsetospeed.c
+++ b/src/termios/cfsetospeed.c
@@ -1,3 +1,4 @@
+#define _BSD_SOURCE
 #include <termios.h>
 #include <sys/ioctl.h>
 #include <errno.h>