Extra Sources Not in Correct Location in Code Generator

[zacnelson]

In version 0.10.4, lines.extend(self._build_extra_sources()) was moved to later in the signals.cpp code. Needs to be bumped up before lines.extend(self._build_signals()) in order for vi-firmware to compile.

vi-firmware compile issue: error: 'customDecoder_in_extra_sources' was not declared in this scope

commit where extra_sources location was changed: 9b867af

fixed in https://github.com/openxc/openxc-python/tree/extra-sources-fix

[peplin]

Merged in the PR, thanks. The takeaway is that any custom C++ code should not be using the static variables in signals.cpp directly, but should access them through the functions in signals.h. This way the order in the file does not matter.