use git archive to build source tarballs

Signed-off-by: Stephan Lachnit <stephanlachnit@protonmail.com>

build-source.sh

@@ -1,10 +1,17 @@
 #!/bin/sh
 
-VERSION=$(git describe --tags --dirty=+)
+VERSION=$(git describe --tags --dirty)
+NAME=MangoHud-$VERSION-Source
 
-FILE_PATTERN="--exclude-vcs --exclude-vcs-ignores ."
-
-# default version
-tar -czf MangoHud-$VERSION-Source.tar.gz $FILE_PATTERN
-# DFSG compliant version, excludes NVML
-tar -czf MangoHud-$VERSION-Source-DFSG.tar.gz --exclude=include/nvml.h $FILE_PATTERN
+# ensure that submodules are present
+git submodule update --init
+# get everything except submodules
+git archive HEAD --format=tar --prefix=${NAME}/ --output=${NAME}.tar
+# add imgui submodule
+tar -rf ${NAME}.tar --exclude-vcs --transform="s,^modules/ImGui/src,${NAME}/modules/ImGui/src," modules/ImGui/src
+# create DFSG compliant version which excludes NVML
+cp ${NAME}.tar ${NAME}-DFSG.tar
+tar -f ${NAME}-DFSG.tar --delete ${NAME}/include/nvml.h
+# compress archives
+gzip ${NAME}.tar
+gzip ${NAME}-DFSG.tar