[sysdep] Add a sysdep for py-yaml

YAML parser and emitter for Python

YAML is a data serialization format designed for human readability and
interaction with scripting languages. PyYAML is a YAML parser and
emitter for Python. PyYAML features a complete YAML 1.1 parser, Unicode
support, pickle support, capable extension API, and sensible error
messages. PyYAML supports standard YAML tags and provides
Python-specific tags that allow to represent an arbitrary Python object.
PyYAML is applicable for a broad range of tasks from complex
configuration files to object serialization and persistance.

sysdep/py-yaml.mk

+# robotpkg sysdep/py-yaml.mk
+# Created:			Arnaud Degroote on Mon,  1 Sep 2014
+#
+DEPEND_DEPTH:=		${DEPEND_DEPTH}+
+PY_YAML_DEPEND_MK:=	${PY_YAML_DEPEND_MK}+
+
+ifeq (+,$(DEPEND_DEPTH))
+DEPEND_PKG+=		py-yaml
+endif
+
+ifeq (+,$(PY_YAML_DEPEND_MK)) # --------------------------------------------
+
+PREFER.py-yaml?=	system
+
+DEPEND_USE+=		py-yaml
+
+DEPEND_ABI.py-yaml?=	${PKGTAG.python}-yaml>=3.0
+
+SYSTEM_SEARCH.py-yaml=\
+  '${PYTHON_SYSLIBSEARCH}/yaml/__init__.py'
+
+SYSTEM_PKG.Debian.py-yaml=	python-yaml (python-${PYTHON_VERSION})
+SYSTEM_PKG.Fedora.py-yaml=	PyYAML 
+SYSTEM_PKG.NetBSD.py-yaml=	textproc/${PKGTAG.python}-yaml
+SYSTEM_PKG.Ubuntu.py-yaml=	python-yaml (python-${PYTHON_VERSION})
+SYSTEM_PKG.Gentoo.py-yaml=	dev-python/pyyaml (python-${PYTHON_VERSION})
+
+include ../../mk/sysdep/python.mk
+
+export YAMLTESTS=	$(word 1,${SYSTEM_FILES.py-yaml})
+
+endif # PY_YAML_DEPEND_MK --------------------------------------------------
+
+DEPEND_DEPTH:=		${DEPEND_DEPTH:+=}