gh-108765: include <unistd.h> in termios.c on Solaris (#108825)

Author: kulikjak

Modules/termios.c

@@ -27,6 +27,9 @@
 
 #include <termios.h>
 #include <sys/ioctl.h>
+#if defined(__sun) && defined(__SVR4)
+#  include <unistd.h>             // ioctl()
+#endif
 
 /* HP-UX requires that this be included to pick up MDCD, MCTS, MDSR,
  * MDTR, MRI, and MRTS (apparently used internally by some things