README: provide basic instructions for building & installing

Fixes #12.

README.md

@@ -2,3 +2,27 @@
 a C++ libary to parse EBML files
 
 Specifications may be rendered at http://matroska-org.github.io/libebml/
+
+# Building and installing
+
+## Building a released version
+
+libebml is based on autoconf and automake and requires only a C++
+compiler. This means that the normal build process consists of the
+usual three steps:
+
+1. Configuration: `./configure`
+2. Building: `make`
+3. Installation (run this as root): `make install`
+
+## Building from git
+
+If you're building from git you must have the GNU autotools
+(`autoconf`, `automake`, `libtoolize`) installed. Then run the
+following two commands:
+
+1. `libtoolize`
+2. `autoreconf -vi`
+
+Afterwards continue with the steps listed for building a released
+version.