Make linux-build POSIX compatible

Also allow it to actually compile on musl-libc systems.

From glibc's termio.h:
/* Compatible <termio.h> for old `struct termio' ioctl interface.
   This is obsolete; use the POSIX.1 `struct termios' interface
   defined in <termios.h> instead.  */

include/common.h

@@ -41,7 +41,8 @@
 #include <limits.h>
 
 #ifdef LINUX
-#include <termio.h>
+#include <termios.h>
+#include <sys/ioctl.h>
 #endif
 
 #ifdef DARWIN

src/shared.c

@@ -2334,12 +2334,12 @@ void drupal7_encode (u8 digest[64], u8 buf[43])
  */
 
 #ifdef LINUX
-static struct termio savemodes;
+static struct termios savemodes;
 static int havemodes = 0;
 
 int tty_break()
 {
-  struct termio modmodes;
+  struct termios modmodes;
 
   if (ioctl (fileno (stdin), TCGETA, &savemodes) < 0) return -1;