From: Niklas Frykholm <r2d2@...>
Date: 2001-08-16T22:41:20+09:00
Subject: [ruby-talk:19895] Re: Compiling Ruby with cygwin and Tk support

On Thu, Aug 16, 2001 at 07:14:06PM +0900, Manuel Zabelt wrote:
> $ ruby extconf.rb
> checking for tcl.h... yes
> checking for tk.h... no
> 
> The tcl.h and tk.h file both rest in /usr/include.
> Why the heck is tcl.h found and tk.h isn't?

Ruby does not only check for existence of the file, it checks that it is
OK to include the file in a program. The problem is that <tk.h> includes
X11-header files which are not normally distributed in a cygwin environment.
You need to get the missing X11-header files, for example by downloading
xfree86 for cygwin (a link was posted here a couple of days ago) and 
put them in the right directories.

I, for one, think that ruby should be more clear about this (an error or
warning should be printed when compiling). As it is now, most users who
try to compile under cygwin will get no warning or error message, but Tk
will simply not work. Finding out why requires a somewhat time-consuming
investigation.

// Niklas