add easy building of git snapshots

add make-git-snapshot.sh to make a tarball from upstream git.
if %global gitcommit is defined on the top, a snapshot is being built.
don't BuildRequire auto-tools to build from release tarballs.

make-git-snapshot.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+set -e
+
+NAME=systemd
+UPSTREAM=git://anongit.freedesktop.org/systemd/systemd
+REFDIR="$HOME/git/systemd"  # for faster cloning, if available
+
+
+[ -n "$1" ] && HEAD="$1" || HEAD="HEAD"
+
+WORKDIR="$(mktemp -d --tmpdir "$NAME.XXXXXXXXXX")"
+trap 'rm -rf $WORKDIR' exit
+
+[ -d "$REFDIR" ] && REFERENCE="--reference $REFDIR"
+git clone $REFERENCE "$UPSTREAM" "$WORKDIR"
+
+pushd "$WORKDIR" > /dev/null
+read COMMIT_ID COMMIT_SHORTID COMMIT_TITLE <<EOGIT
+$(git log ${HEAD}^..${HEAD} --pretty='format:%H %h %s')
+EOGIT
+popd > /dev/null
+
+echo "Making git snapshot using commit: $COMMIT_SHORTID $COMMIT_TITLE"
+
+DIRNAME="$NAME-git$COMMIT_SHORTID"
+git archive --remote="$WORKDIR" --format=tar --prefix="$DIRNAME/" "$COMMIT_ID" | xz -9 > "$DIRNAME.tar.xz"
+
+echo "Written $DIRNAME.tar.xz"

systemd.spec

@@ -1,8 +1,9 @@
+#% global gitcommit 3e52541
 Name:           systemd
 Url:            http://www.freedesktop.org/wiki/Software/systemd
 BuildRoot:      %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 Version:        38
-Release:        4%{?dist}
+Release:        4%{?gitcommit:.git%{gitcommit}}%{?dist}
 License:        GPLv2+
 Group:          System Environment/Base
 Summary:        A System and Service Manager
@@ -22,15 +23,17 @@ BuildRequires:  glib2-devel
 BuildRequires:  libgee06-devel
 BuildRequires:  libnotify-devel >= 0.7
 BuildRequires:  libacl-devel
-BuildRequires:  automake
-BuildRequires:  autoconf
-BuildRequires:  libtool
 BuildRequires:  make
 BuildRequires:  intltool >= 0.40.0
 BuildRequires:  binutils
 BuildRequires:  gperf
 BuildRequires:  gawk
 BuildRequires:  xz-devel
+%if %{defined gitcommit}
+BuildRequires:  automake
+BuildRequires:  autoconf
+BuildRequires:  libtool
+%endif
 Requires(post): authconfig
 Requires:       systemd-units = %{version}-%{release}
 Requires:       dbus >= 1.4.6-3.fc15
@@ -41,7 +44,12 @@ Requires:       filesystem >= 2.4.40
 Conflicts:      selinux-policy < 3.9.16-12.fc15
 Conflicts:      kernel < 2.6.35.2-9.fc14
 Requires:       nss-myhostname
+%if %{defined gitcommit}
+# Snapshot tarball can be created using: ./make-git-shapshot.sh [gitcommit]
+Source0:        %{name}-git%{gitcommit}.tar.xz
+%else
 Source0:        http://www.freedesktop.org/software/systemd/%{name}-%{version}.tar.xz
+%endif
 # Adds support for the %%{_unitdir} macro
 Source1:        macros.systemd
 Source2:        systemd-sysv-convert
@@ -112,10 +120,11 @@ Requires:       %{name} = %{version}-%{release}
 SysV compatibility tools for systemd
 
 %prep
-%setup -q
+%setup -q %{?gitcommit:-n %{name}-git%{gitcommit}}
 %patch0 -p1 -b .big-endian
 
 %build
+%{?gitcommit: ./autogen.sh }
 %configure --with-rootprefix= --with-distro=fedora --with-rootlibdir=/%{_lib}
 make %{?_smp_mflags}