Add support for SOURCE_DATE_EPOCH

NEWS

@@ -3,6 +3,7 @@ Changes in 1.NNN, released on YYYY-MM-DD:
 * Fix regression when streaming formats other than Ogg (e.g. MP3). From
   zygmund2000 on Github (#30) and Roland Hermans on GitLab (#2271).
 * Fix build issue on OSX. From Mitchell Blank on GitLab (#2270).
+* Support reproducible builds. Via Unit 193 on GitLab (#2276).
 * Update autoconf requirement to 2.69
 
 

configure.ac

@@ -15,8 +15,16 @@ AC_PROG_CC_STDC
 AC_PROG_FGREP
 AC_CANONICAL_HOST
 
-BUILD_DATE=$(date '+%B %d, %Y')
-AC_SUBST([BUILD_DATE])
+SOURCE_DATE=$(date '+%B %d, %Y')
+if test -n "${SOURCE_DATE_EPOCH}"; then
+	if test -n "$(date --version 2> /dev/null | head -n 1 | grep GNU)"; then
+		SOURCE_DATE="$(LC_ALL=C date -u -d "@${SOURCE_DATE_EPOCH}" '+%B %d, %Y')"
+	else
+		# Assume BSD date
+		SOURCE_DATE="$(LC_ALL=C date -u -r "${SOURCE_DATE_EPOCH}" '+%B %d, %Y')"
+	fi
+fi
+AC_SUBST([SOURCE_DATE])
 
 EXAMPLES_DIR="\$(datadir)/examples/${PACKAGE_TARNAME}"
 AC_ARG_ENABLE([examplesdir],

doc/ezstream-cfgmigrate.1.in.in

@@ -12,7 +12,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd @BUILD_DATE@
+.Dd @SOURCE_DATE@
 .Dt EZSTREAM-CFGMIGRATE 1
 .Os @PACKAGE_NAME@ @PACKAGE_VERSION@
 .Sh NAME

doc/ezstream-file.sh.1.in.in

@@ -12,7 +12,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd @BUILD_DATE@
+.Dd @SOURCE_DATE@
 .Dt EZSTREAM-FILE.SH 1
 .Os @PACKAGE_NAME@ @PACKAGE_VERSION@
 .Sh NAME

doc/ezstream.1.in.in

@@ -9,7 +9,7 @@
 .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 .\" GNU General Public License for more details.
 .\"
-.Dd @BUILD_DATE@
+.Dd @SOURCE_DATE@
 .Dt EZSTREAM 1
 .Os @PACKAGE_NAME@ @PACKAGE_VERSION@
 .Sh NAME