Merge pull request libjpeg-turbo#4 from oerdnj/master

Allow BUILD to be specified on the configure command line

configure.ac

@@ -3,7 +3,6 @@
 
 AC_PREREQ([2.56])
 AC_INIT([libjpeg-turbo], [1.4.80])
-BUILD=`date +%Y%m%d`
 
 AM_INIT_AUTOMAKE([-Wall foreign dist-bzip2])
 AC_PREFIX_DEFAULT(/opt/libjpeg-turbo)
@@ -22,6 +21,10 @@ AC_PROG_INSTALL
 AC_PROG_LIBTOOL
 AC_PROG_LN_S
 
+AC_ARG_WITH([build-date], [Use custom build string to enable reproducible builds (default: YYMMDD)],
+  [BUILD="$with_build_date"],
+  [BUILD=`date +%Y%m%d`])
+
 # When the prefix is /opt/libjpeg-turbo, we assume that an "official" binary is
 # being created, and thus we install things into specific locations.