diff --git a/doc/developer/Makefile b/doc/developer/Makefile
index ecfd16b47281b022d2623f8e37e4012990a228ea..ade59e570a6d44e96faa4e8c34b58738bffa583f 100644
--- a/doc/developer/Makefile
+++ b/doc/developer/Makefile
@@ -144,8 +144,13 @@ check-viewcfg-v5:
 check-viewcfg-v6:
 	cd tutorial/viewcfg/v6-* && $(duneb) @install
 
-hello.tar: FILES= $(shell cd tutorial/hello/v7-doc && git ls-files)
+ifdef NIX_BUILD_TOP
+# - in Nix CI we expect the directory to be clean
+hello.tar: FILES= $(shell cd tutorial/hello/v7-doc && find *)
+else
 # - use 'git ls-files' to avoid including extraneous files in archive
+hello.tar: FILES= $(shell cd tutorial/hello/v7-doc && git ls-files)
+endif
 # - use several tar options to improve build reproducibility
 hello.tar:
 	cd tutorial/hello && \
@@ -153,12 +158,13 @@ hello.tar:
 	cp -r v7-doc hello && \
 	tar -cf $@ $(addprefix hello/,$(FILES)) \
 	  --numeric-owner --owner=0 --group=0 --sort=name \
-	  --mtime="$$(date +"%F") Z" --mode='a+rw'
+	  --mtime="$$(date +"%F") Z" --mode='a+rw' && \
+	rm -rf hello && \
+	mv hello.tar ../../hello.tar
 
 hello.tar.gz: hello.tar
-	cd tutorial/hello && \
-	gzip -9 -n hello.tar > ../../hello.tar.gz && \
-	rm -rf hello hello.tar
+	gzip -9 -ncf hello.tar > hello.tar.gz && \
+	rm -rf hello.tar
 
 ###########
 
diff --git a/nix/manuals.nix b/nix/manuals.nix
index 23d21eb871f4c58969182bd7968a9ba139ac5435..30bdbd93afd69a11f16babfe9805cca8a0ecb5c2 100644
--- a/nix/manuals.nix
+++ b/nix/manuals.nix
@@ -1,7 +1,6 @@
 { lib
 , stdenv
 , frama-c
-, git
 , headache
 , texlive
 } :
@@ -26,7 +25,6 @@ stdenv.mkDerivation rec {
 
   buildInputs = frama-c.buildInputs ++ [
     frama-c
-    git
     headache
     texlive.combined.scheme-full
   ];