verify that dependencie is correctly downloaded

latex/presentation/Makefile

@@ -3,6 +3,7 @@ NAME  = slides
 TEX = $(NAME).tex
 SRC = $(TEX)
 PDF = $(TEX:.tex=.pdf)
+PKG = projektor.sty
 
 TEXMK = latexmk -lualatex -shell-escape
 WGET  = wget -q --show-progress
@@ -11,7 +12,11 @@ WGET  = wget -q --show-progress
 all: $(PDF)
 
 $(PDF): %.pdf: %.tex
-	$(TEXMK) $<
+ifneq (,$(wildcard $(PKG)))
+	@$(TEXMK) $<
+else
+	@echo "Can't proceed, $(PKG) missing."
+endif
 
 EXTS = aux fdb_latexmk fls log nav out snm synctex.gz toc vrb
 clean:
@@ -19,4 +24,4 @@ clean:
 
 updatepackage:
 	@$(WGET) https://git.mylloon.fr/Anri/projektor/raw/branch/main/projektor.sty \
-		-O projektor.sty
+		-O $(PKG)