added information on how to create fake debian packages

added information on how to create fake debian packages. This may be useful to allow apt to use locally compiled poppler installations.

Author: stephengaito

docs/FakePackages.md

@@ -0,0 +1,48 @@
+# Creating fake Debian Packages
+
+When developing pdf2htmlEX on a platform such as Ubuntu which has
+*older* versions of poppler than the one you are developing
+pdf2htmlEX to match... you sometimes need to fake things!
+
+You can do this by using the
+[Debian equivs](https://salsa.debian.org/perl-team/modules/packages/equivs)
+package.
+
+---
+
+To build a fake dpkg to assert that some real package has been 
+installed locally from source you type:
+
+    sudo apt install equivs
+
+This will install all of the required commands.
+
+Then type: 
+
+    equivs-control <<nameOfPackage>>-fake
+
+This will create a template debian package manager file for use in the 
+following two steps.
+
+Then edit the `<<nameOfPackage>>-fake` control file by typing:
+
+    nano <<nameOfPackage>>-fake
+
+Edit the `<<nameOfPackage>>-fake` file to provide correct debian package 
+details.  The most important two lines are the "Package" name (which 
+should be `<<nameOfPackage>>-fake`) and "Provides" (which should be the 
+name(s) of the packages which this fake package is asserting are 
+already provided on this local system).
+
+Once you have finished your edits, type:
+
+    equivs-build <<nameOfPackage>>-fake
+
+This will build the fake debian package.
+
+---
+
+The above has been adapted from the article:
+[Debian Package Management, Part 2: A Developer's Guide](http://www.linuxjournal.com/article/4610)
+or from the section 15.2.1. "Meta-Packages or Fake Packages" of the
+[Debian handbook guide](http://debian-handbook.info/browse/stable/sect.building-first-package.html#idp19964272).