Debian 9 introduced patch into pip, which auto-adds "--user" parameter

to pip, which cannot work with "--target". Therefore, "make" fails on
current Debian stable (Stretch, 9). Just adding "--system" before "-t"
fixes that. Yes, it's stupid, but it works. For more info, see:
pypa/pip#3826

Author: haimgel

Makefile

@@ -9,7 +9,7 @@ BUILD_DIR=build
 haaska.zip: haaska.py config/*
 	mkdir -p $(BUILD_DIR)
 	cp $^ $(BUILD_DIR)
-	pip install -t $(BUILD_DIR) requests
+	pip install --system -t $(BUILD_DIR) requests
 	cd $(BUILD_DIR); zip ../$@ -r *
 
 .PHONY: deploy