Added 'Linkers and Loaders' book

Not quite sure but the 'compilers' section seems to be the closest fit.  Author has freely downloadable manuscript in TROFF and Postscript and links to purchase hard copy on Amazon etc

free-programming-books.md

@@ -268,6 +268,7 @@
 * [Compiling Scala for the Java Virtual Machine](http://lampwww.epfl.ch/~schinz/thesis-final-A4.pdf) - Michel Schinz
 * [Implementing Functional Languages: A Tutorial](http://research.microsoft.com/en-us/um/people/simonpj/Papers/pj-lester-book/) - Simon Peyton Jones, David Lester
 * [Let's Build a Compiler](http://www.stack.nl/~marcov/compiler.pdf) (PDF)
+* [Linkers and Loaders](http://www.iecc.com/linker/) - John R. Levine
 * [Practical and Theoretical Aspects of Compiler Construction](http://www.stanford.edu/class/archive/cs/cs143/cs143.1128/) (class lectures and slides)