Build System: Convert Python scripts to python3 (#138)

* Build System: Convert Python scripts to `python3`

Change `Makefile` to invoke the Python scripts using the `python3` interpreter,
as well as using the `2to3` suggested changes to the scripts. Please note that
the s/long/int/ change is not taken, as the python3-git module has a "long" option
(for a `git describe` binding) which is obviously not an integer type but requests
the long listing format...

* Fix 2to3 oddities

src/Makefile

@@ -12,7 +12,7 @@ export STM32F4XX ?= 1
 # Set to 1 HYDRAFW_NFC to include HydraNFC extension support
 export HYDRAFW_NFC ?= 1
 export HYDRAFW_DEBUG ?= 0
-export FW_REVISION := $(shell python build-scripts/hydrafw-revision.py)
+export FW_REVISION := $(shell python3 build-scripts/hydrafw-revision.py)
 
 HYDRAFW_OPTS =
 
@@ -316,19 +316,19 @@ FORCE:
 ifeq ($(USE_VERBOSE_COMPILE),yes)
  echo Creating ./common/hydrafw_version.hdr
  -rm -f $(OBJDIR)/common.o
- python build-scripts/hydrafw-version.py ./common/hydrafw_version.hdr
+ python3 build-scripts/hydrafw-version.py ./common/hydrafw_version.hdr
 else
  @echo Creating ./common/hydrafw_version.hdr
  @rm -f $(OBJDIR)/common.o
- @python build-scripts/hydrafw-version.py ./common/hydrafw_version.hdr
+ @python3 build-scripts/hydrafw-version.py ./common/hydrafw_version.hdr
 endif
 
 %.dfu: %.hex $(LDSCRIPT)
 ifeq ($(USE_VERBOSE_COMPILE),yes)
- python build-scripts/dfu-convert.py -r $(FW_REVISION) -i $< $@
+ python3 build-scripts/dfu-convert.py -r $(FW_REVISION) -i $< $@
 else
  @echo Creating $@
- @python build-scripts/dfu-convert.py -r $(FW_REVISION) -i $< $@
+ @python3 build-scripts/dfu-convert.py -r $(FW_REVISION) -i $< $@
 endif
 
 # This rule hook is defined in the ChibiOS build system

src/build-scripts/dfu-convert.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python2
+#!/usr/bin/env python3
 
 # Written by Antonio Galea - 2010/11/18
 # Distributed under Gnu LGPL 3.0

src/build-scripts/hydrafw-revision.py

@@ -1,3 +1,5 @@
+#!/usr/bin/env python3
+
 from git import *
 import re
 

src/build-scripts/hydrafw-version.py

@@ -1,3 +1,5 @@
+#!/usr/bin/env python3
+
 import sys
 from optparse import OptionParser
 from datetime import *