For discussion of the package internals, see hackguide.html in the misc
directory.

Here are some -D options you might need to compile with.
The 'configure' script usually gets them right automatically.
  
-DHAVE_UNISTD_H		if <unistd.h> is present

-DHAVE_SIGACTION	if the sigaction function is present

-DHAVE_USLEEP		if the usleep function is present

-DSTRICTPOSIX		if _POSIX_SOURCE turns off non-POSIX features.

-DSVR4_ACTION		if (e.g., svr4) you need _POSIX_SOURCE to have sigaction

-DHAVE_TERMIOS_H	if you have <termios.h>; otherwise it uses <sgtty.h>

-DOPT_MVCUR		if you want mvcur() to cost its actions or you have a
			terminal that doesn't have direct cursor addressing.

-D_HPUX_SOURCE		so that we get POSIX and XOPEN features.

-DBROKEN_TIOCGETWINSZ	on SVR4 and HPUX

-DHAVE_SYS_SELECT_H	if (e.g., AIX) you have <sys/select.h>

There are several problems with strict POSIX systems so extra flags
or #define's may be needed.

	HP-UX:	-D_HPUX_SOURCE so that we get POSIX and XOPEN features.
	SVR4:	-DBROKEN_TIOCGETWINSZ guess what?

