Fix `make requirements` on osx
Beforehand, it was throwing
```
# Setup PYTHONPATH in bash activate script...
# Delete existing entries (if any)
sed -i '/_OLD_PYTHONPATHp/d' virtualenv-osx/bin/activate
sed: 1: "virtualenv-osx/bin/acti ...": invalid command code v
make: *** [virtualenv] Error 1
```
@@ -376,9 +376,15 @@ virtualenv:
# Setup PYTHONPATH in bash activate script...
# Delete existing entries (if any)
+ ifeq ($(OS),Darwin)
+ sed -i '' '/_OLD_PYTHONPATHp/d' $(VIRTUALENV_DIR)/bin/activate
+ sed -i '' '/PYTHONPATH=/d' $(VIRTUALENV_DIR)/bin/activate
+ sed -i '' '/export PYTHONPATH/d' $(VIRTUALENV_DIR)/bin/activate
+ else
sed -i '/_OLD_PYTHONPATHp/d' $(VIRTUALENV_DIR)/bin/activate
sed -i '/PYTHONPATH=/d' $(VIRTUALENV_DIR)/bin/activate
sed -i '/export PYTHONPATH/d' $(VIRTUALENV_DIR)/bin/activate
+ endif
echo '_OLD_PYTHONPATH=$$PYTHONPATH' >> $(VIRTUALENV_DIR)/bin/activate
#echo 'PYTHONPATH=$$_OLD_PYTHONPATH:$(COMPONENT_PYTHONPATH)' >> $(VIRTUALENV_DIR)/bin/activate
