Update docos to mention CGI mode and data: URIs are connected to HTTP/HTTPS support (Issue #547)

Author: michaelrsweet

INSTALL.md

@@ -12,7 +12,7 @@ To compile HTMLDOC you'll need C and C++ compilers (clang and gcc are fine)
 along with the following libraries:
 
 - FLTK 1.3.x+ for GUI support
-- CUPS 2.2+ for HTTP/HTTPS support
+- CUPS 2.2+ for HTTP/HTTPS, CGI mode, and "data:" URI support
 - libjpeg 7+ or libjpeg-turbo for JPEG support
 - libpng 1.6+ or higher for PNG support
 - zlib 1.1+ or higher

doc/2-using.html

@@ -122,6 +122,10 @@ <h2><a name='CGI'>Using HTMLDOC on a Web Server</a></h2>
 
 <h3>CGI Mode</h3>
 
+<blockquote><b>Note:<b> CGI mode is only available when HTMLDOC is compiled with
+HTTP/HTTPS support.  The snap and MSI versions of HTMLDOC both include support
+for CGI mode and HTTP/HTTPS references.</blockquote>
+
 <p>HTMLDOC supports operation as a CGI program. You can copy or symlink the <var>htmldoc</var> (all but Windows) or <var>htmldoc.exe</var> (Windows) executable to your web server's <var>cgi-bin</var> directory and then use it to produce PDF versions of your web pages.</p>
 
 <p>The CGI converts a page on your local server to PDF and sends it to the client's web browser. For example, to convert a page called <var>superproducts.html</var> at the following URL:</p>