Missing build step for linux

[bedeho]

In explanation of how to setup build environment on linux (master/docs/linux-build-environment),
before 7) "Build qrencode QR Code C library (libqrencode) for linux", one must install libpng, e.g. using sudo apt-get install libpng-dev

[fansari]

I had to do the following steps to build for Linux:

Downgrade gcc to 5.1.1 in order to install odb.

The DB was not recognized unless I do something like this:
ln -s /usr/lib64/libodb-sqlite.so /usr/local/lib/libodb-sqlite.so

In order to link the application I had to add the -fPIC option to the C_FLAGS and CXX_FLAGS in c_flags.mk and cxx_flags.mk in the deps/mk directory.

Version: afc6cf2
System: Fedora 23 (x86_64)