Building PyPy from Source
+For building PyPy, it is recommended to install a pre-build PyPy first (see
+:doc:`install`). It is possible to build PyPy with CPython, but it will take a
+lot longer to run -- depending on your architecture, between two and three
+Even when using PyPy to build PyPy, translation is time-consuming -- 30
+minutes on a fast machine -- and RAM-hungry. You will need **at least** 2 GB
+of memory on a 32-bit machine and 4GB on a 64-bit machine.
+Install build-time dependencies
+To build PyPy on Unix using the C translation backend, you need at least a C
+compiler and ``make`` installed. Further, some optional modules have additional
+ libncurses + cffi dependencies from above
+Make sure to have these libraries (with development headers) installed before
+building PyPy, otherwise the resulting binary will not contain these modules.
+On Debian, this is the command to install all build-time dependencies::
+ apt-get install gcc make libffi-dev pkg-config libz-dev libbz2-dev \
+ libsqlite3-dev libncurses-dev libexpat1-dev libssl-dev
+ yum install gcc make libffi-devel pkgconfig zlib-devel bzip2-devel \
+ lib-sqlite3-devel ncurses-devel expat-devel openssl-devel
+ pypy rpython/bin/rpython --opt=jit pypy/goal/targetpypystandalone.py
+ pypy rpython/bin/rpython --opt=2 pypy/goal/targetpypystandalone.py
+If everything works correctly this will create an executable ``pypy-c`` in the
+current directory. The executable behaves mostly like a normal Python
+interpreter (see :doc:`cpython differences`).
+PyPy dynamically finds the location of its libraries depending on the location
+of the executable. The directory hierarchy of a typical PyPy installation
+The hierarchy shown above is relative to a PREFIX directory. PREFIX is
+computed by starting from the directory where the executable resides, and
+"walking up" the filesystem until we find a directory containing ``lib_pypy``
+To install PyPy system wide on unix-like systems, it is recommended to put the
+whole hierarchy alone (e.g. in ``/opt/pypy``) and put a symlink to the
+``pypy`` executable into ``/usr/bin`` or ``/usr/local/bin``.
+If the executable fails to find suitable libraries, it will report ``debug:
+WARNING: library path not found, using compiled-in sys.path`` and then attempt
+to continue normally. If the default path is usable, most code will be fine.
+However, the ``sys.prefix`` will be unset and some existing libraries assume
+that this is never the case.