Makefile: add alli5 target

make -j $(nproc) alli5 SRC_DIR=<dir with *.epub>

should be the target, for now
diff --git a/Makefile b/Makefile
index a15d5be..4122008 100644
--- a/Makefile
+++ b/Makefile
@@ -6,6 +6,7 @@
 DEPLOY_PATH ?= /export/netapp/korap4dnb
 MAX_THREADS ?= $(shell nproc)
 YY ?= 18
+MAKE ?= make -j $(shell nproc)
 
 .PHONY: all clean test i5 i5valid krill index deploy server-log server-status
 
@@ -97,3 +98,7 @@
 clean:
 	rm -rf $(BUILD_DIR) $(TARGET_DIR)
 
+alli5:
+	for yy in {98..99} {00..23}; do \
+	    $(MAKE) i5 YY=$$yy; \
+	done