Add missing #include to support TIOCGWINSZ on Solaris

On Linux TIOCGWINSZ is defined somehwere in ioctl.h, which is already
included. On Solaris we also need to include termios.h. Without this
term_columns() in help.c will think TIOCGWINSZ is not supported and
always return 80 columns.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-compat-util.h

@@ -96,6 +96,7 @@
 #include <sys/poll.h>
 #include <sys/socket.h>
 #include <sys/ioctl.h>
+#include <termios.h>
 #ifndef NO_SYS_SELECT_H
 #include <sys/select.h>
 #endif