Rename README files to README.txt (and several similar files).

Files without '.txt' suffix can't be handled well by Windows (users),
hence renaming such text files to *.txt makes FLTK more "Windows-friendly".

There are a few exceptions (this is intentional): README and other files
in bundled libraries (maintained upstream) are not changed.

2 files changed, 44 insertions, 45 deletions

diff --git a/documentation/README b/documentation/README.txt
index 7fa1151e9..6b7e39980 100644
--- a/documentation/README
+++ b/documentation/README.txt
@@ -1,12 +1,11 @@
-README (documentation)
-----------------------
+README.txt (documentation)
+---------------------------
 FLTK 1.3 (and higher) documentation is available in HTML and PDF format.
 The documentation must be generated in a separate step or downloaded
 from FLTK's software download pages. The documentation can also
 be accessed online.
 
-To read the docs after downloading or generating them, open the
-files:
+To read the docs after downloading or generating them, open the files:
 
     documentation/html/index.html
     documentation/fltk.pdf
@@ -21,14 +20,14 @@ along with the PDF version of the manual. The docs on the web site
 are usually somewhat older (latest release). Use this URL to find
 the current online documentation:
 
-    http://www.fltk.org/documentation.php
+    https://www.fltk.org/documentation.php
 
 
 Documentation Download:
 -----------------------
 To download pre-generated docs, go to
 
-    http://www.fltk.org/software.php
+    https://www.fltk.org/software.php
 
 and look for the files
 
@@ -42,13 +41,18 @@ did with the source tarball.
 Generation of Documentation (common part):
 ------------------------------------------
 To generate the documentation yourself, you should have Doxygen
-version 1.5.7 or later (recommended version is 1.7.3 or later).
+version 1.8 or later (recommended version is 1.8.13 or later).
+Older Doxygen versions than 1.8 may or may not work.
 
 To generate the PDF version you also need a current version of LaTeX.
 You can use the packages tetex (older) or texlive (current) if your
 distribution provides them. You may need to install additional fonts
 and other sub-packages for the PDF version to be generated correctly.
 
+Note: packages known to work under Ubuntu 18.04:
+
+  texlive texlive-extra-utils texlive-latex-extra texlive-font-utils
+
 
 Generation of Documentation with autoconf (configure) + make:
 -------------------------------------------------------------
@@ -91,10 +95,10 @@ manually, because the generation is not included in the standard ('all')
 target. This may be changed in the future.
 
 
-FLTK Developer Snapshots or Subversion Usage:
----------------------------------------------
+FLTK Developer Snapshots or Git Usage:
+--------------------------------------
 There is no pre-generated documentation available if you use a current
-developer snapshot or subversion. You must generate the documentation
+developer snapshot or git. You must generate the documentation
 yourself or access the online documentation.
 
 
@@ -105,4 +109,4 @@ contribute an example, section, or chapter to the FLTK manual, please
 post a question in the fltk newsgroup fltk.general or post a bug
 report or feature request at:
 
-    http://www.fltk.org/str.php
+    https://www.fltk.org/str.php
diff --git a/documentation/src/intro.dox b/documentation/src/intro.dox
index cfb7d1c10..7213fbba5 100644
--- a/documentation/src/intro.dox
+++ b/documentation/src/intro.dox
@@ -5,7 +5,7 @@
 The Fast Light Tool Kit ("FLTK", pronounced
 "fulltick") is a cross-platform C++ GUI toolkit for
 UNIX®/Linux® (X11), Microsoft® Windows®, and
-Apple® OS X®. FLTK provides modern GUI functionality without the
+Apple® macOS®. FLTK provides modern GUI functionality without the
 bloat and supports 3D graphics via OpenGL® and its built-in
 GLUT emulation. It was originally developed by Mr. Bill Spitzak
 and is currently maintained by a small group of developers
@@ -143,13 +143,10 @@ the toolkit, which was already in use by several people, Bill
 came up with "FLTK", including a bogus excuse that it
 stands for "The Fast Light Toolkit".
 
-\section intro_unix Building and Installing FLTK Under UNIX and Apple OS X
+\section intro_unix Building and Installing FLTK Under UNIX and Apple macOS
 
-In most cases you can just type "make". This will
-run configure with the default of no options and then compile
-everything.
-
-For OS X, Xcode 3 project files can be found in the 'ide' directory.
+In most cases you can just type "make". This will run configure with
+the default of no options and then compile everything.
 
 FLTK uses GNU autoconf to configure itself for your UNIX
 platform. The main things that the configure script will look
@@ -268,37 +265,34 @@ with object files from any of the other environments!
 (They use incompatible C++ conventions internally.)
 
 Free Microsoft Visual C++ 2008 Express and Visual C++ 2010 Express
-or later versions using the supplied workspace and
-project files. Older versions, and the commercial
-versions, can be used as well, if they can open
-the project files.
+or later versions using workspace and project files generated by CMake.
+Older versions and the commercial versions can be used as well, if they
+can open the project files.
 Be sure to get your service packs!
 
-The project files can be found in the "ide/" directory.
-Please read "ide/README.IDE" for more info about this.
+Since FLTK 1.4 the project files MUST be generated with CMake.
+Please read "README.CMake.txt" for more information about this.
 
 
 \subsection intro_cygwin_mingw GNU toolsets (Cygwin or MinGW) hosted on Windows
 
-If using Cygwin with the Cygwin shell, or MinGW with
-the Msys shell, these build environments behave very
-much like a Unix or OS X build and the notes above in
-the section on
-<i>Building and Installing FLTK Under UNIX and Apple OS X</i>
+If using Cygwin with the Cygwin shell, or MinGW with the Msys shell,
+these build environments behave very much like a Unix or macOS build
+and the notes above in the section on
+<i>Building and Installing FLTK Under UNIX and Apple macOS</i>
 apply, in particular the descriptions of using the
 "configure" script and its related options.
 
-In general for a build using these tools, e.g. for
-the Msys shell with MinGW,
-it should suffice to "cd" into the directory where
-you have extracted the fltk tarball and type:
+In general for a build using these tools, e.g. for the Msys shell with
+MinGW, it should suffice to "cd" into the directory where you have
+extracted the FLTK tarball and type:
 
 \code
 ./configure
 make
 \endcode
 
-This will build the fltk libraries and they can then be
+This will build the FLTK libraries and they can then be
 utilised directly from the build location.
 NOTE: this may be simpler than "installing" them in
 many cases as different tool chains on Windows have
@@ -319,7 +313,7 @@ something like "C:\msys\1.0\local\lib", depending
 on where your Msys installation is rooted, which may
 not be useful to other tools.
 
-If you want to install your built fltk libraries in a
+If you want to install your built FLTK libraries in a
 non-standard location you may do:
 
 \code
@@ -328,10 +322,10 @@ make
 \endcode
 
 Where the value passed to "prefix" is the path at which
-you would like fltk to be installed.
+you would like FLTK to be installed.
 
 A subsequent invocation of "make install" will then place
-the fltk libraries and header files into that path.
+the FLTK libraries and header files into that path.
 
 The other options to "configure" may also be used to
 tailor the build to suit your environment.
@@ -354,28 +348,29 @@ header files.
 FLTK is available on the 'net in a bunch of locations:
 
 \par WWW
-http://www.fltk.org/ <br>
-http://www.fltk.org/str.php [for reporting bugs] <br>
-http://www.fltk.org/software.php [source code]<br>
-http://www.fltk.org/newsgroups.php [newsgroup/forums]
+https://www.fltk.org/ <br>
+https://www.fltk.org/str.php [for reporting bugs] <br>
+https://www.fltk.org/software.php [download source code]<br>
+https://www.fltk.org/newsgroups.php [newsgroup/forums]
 
 \par NNTP Newsgroups
 https://groups.google.com/forum/#!forum/fltkgeneral [Google Groups interface]
 news://fltk.org:1024/ [NNTP interface]<br>
-http://fltk.org/newsgroups.php [web interface]<br>
+https://www.fltk.org/newsgroups.php [web interface]<br>
 
 \section intro_reporting Reporting Bugs
 
 To report a bug in FLTK, or for feature requests, please use the form at
-<A href="http://www.fltk.org/str.php">http://www.fltk.org/str.php</A>,
+<A href="https://www.fltk.org/str.php">https://www.fltk.org/str.php</A>,
 and click on "Submit Bug or Feature Request".
 
 You'll be prompted for the FLTK version, operating system & version,
 and compiler that you are using. We will be unable to provide
 any kind of help without that basic information.
 
-For general support and questions, please use the fltk.general newsgroup (see above, "NNTP Newsgroups")
-or the web interface to the newsgroups at <A href="http://fltk.org/newsgroups.php">http://fltk.org/newsgroups.php</A>.
+For general support and questions, please use the fltk.general newsgroup
+(see above, "NNTP Newsgroups") or the web interface to the newsgroups at
+<A href="https://www.fltk.org/newsgroups.php">https://www.fltk.org/newsgroups.php</A>.
 
 \htmlonly
 <hr>