3 files changed, 45 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index 7b991f5..6e0b3dd 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,5 @@
 V=20210202
+BUILDTOOLVER ?= $(V)-git
 
 PREFIX = /usr/local
 MANDIR = $(PREFIX)/share/man
@@ -92,7 +93,7 @@ edit = sed -e "s|@pkgdatadir[@]|$(PREFIX)/share/devtools|g"
 %: %.in Makefile lib/common.sh
 	@echo "GEN $@"
 	@$(RM) "$@"
-	@{ echo -n 'm4_changequote([[[,]]])'; cat $@.in; } | m4 -P --define=m4_devtools_version=$V | $(edit) >$@
+	@{ echo -n 'm4_changequote([[[,]]])'; cat $@.in; } | m4 -P --define=m4_devtools_version=$(BUILDTOOLVER) | $(edit) >$@
 	@chmod a-w "$@"
 	@chmod +x "$@"
 	@bash -O extglob -n "$@"
diff --git a/README.md b/README.md
index 0f5d8f2..c4bc8f4 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,17 @@ as following.
 git config format.subjectprefix 'devtools] [PATCH'
 ```
 
+## Building
+
+When building official distro packages the `BUILDTOOLVER` needs to be set to the
+exact label of the release package in order to allow to detect the exactly used
+devtools version. This is required for reproducible builds to fetch the according
+files like `makepkg.conf`.
+
+```sh
+BUILDTOOLVER="${pkgver}-${pkgrel}-${arch}" make all
+```
+
 ## Releasing
 
 1. bump the version in the Makefile
diff --git a/makerepropkg.in b/makerepropkg.in
index ec9cd36..70abcbe 100755
--- a/makerepropkg.in
+++ b/makerepropkg.in
@@ -81,6 +81,18 @@ get_pkgfile() {
     return 1
 }
 
+get_makepkg_conf() {
+    local fname=${1}
+    local makepkg_conf="${2}"
+    if ! buildtool_file=$(get_pkgfile "${fname}"); then
+        error "failed to retrieve ${fname}"
+        return 1
+    fi
+    msg2 "using makepkg.conf from ${fname}"
+    bsdtar xOqf "${buildtool_file/file:\/\//}" usr/share/devtools/makepkg-x86_64.conf > "${makepkg_conf}"
+    return 0
+}
+
 usage() {
     cat << __EOF__
 usage: ${BASH_SOURCE[0]##*/} [options] <package_file>
@@ -185,7 +197,26 @@ for fname in "${installed[@]}"; do
         exit 1
     fi
 done
-printf '%s\n' "${allpkgfiles[@]}" | mkarchroot -M @pkgdatadir@/makepkg-x86_64.conf -U "${archroot_args[@]}" "${buildroot}"/root - || exit 1
+
+trap 'rm -rf $TEMPDIR' EXIT INT TERM QUIT
+TEMPDIR=$(mktemp -d --tmpdir makerepropkg.XXXXXXXXXX)
+
+makepkg_conf="${TEMPDIR}/makepkg.conf"
+# anything before buildtool support is pinned to the last none buildtool aware release
+if [[ -z "${BUILDTOOL}" ]]; then
+    get_makepkg_conf "devtools-20210202-3-any" "${makepkg_conf}" || exit 1
+# prefere to assume devtools up until matching makepkg version so repository packages remain reproducible
+elif [[ "${BUILDTOOL}" = makepkg ]] && (( $(vercmp "${BUILDTOOLVER}" 6.0.1) <= 0 )); then
+    get_makepkg_conf "devtools-20210202-3-any" "${makepkg_conf}" || exit 1
+# all devtools builds
+elif [[ "${BUILDTOOL}" = devtools ]] && get_makepkg_conf "${BUILDTOOL}-${BUILDTOOLVER}" "${makepkg_conf}"; then
+    true
+# fallback to current makepkg.conf
+else
+    warning "Unknown buildtool (${BUILDTOOL}-${BUILDTOOLVER}), using fallback"
+    makepkg_conf=@pkgdatadir@/makepkg-x86_64.conf
+fi
+printf '%s\n' "${allpkgfiles[@]}" | mkarchroot -M "${makepkg_conf}" -U "${archroot_args[@]}" "${buildroot}"/root - || exit 1
 
 # use makechrootpkg to prep the build directory
 makechrootpkg -r "${buildroot}" -l "${chroot}" -- --packagelist || exit 1