Support SOURCE_DATE_EPOCH for deterministic builds.

Author: swaldman

CHANGELOG

@@ -1,6 +1,13 @@
+	-- Support SOURCE_DATE_EPOCH for deterministic builds.
+	   (Here and in mchange-commons-java.)
+	   See https://github.com/swaldman/c3p0/issues/163
+	       https://reproducible-builds.org/docs/source-date-epoch/
+	       https://github.com/swaldman/mchange-commons-java/commit/09480482ddde70b98baf8437e66c5e3bba9ae3e2
+	   Thanks Bernhard M. Wiedemann!
 	-- Eliminate support for traditional reflective proxies.
 	-- Fix bad anchor in docs, thanks Hakan!
 	-- Relicense to allow users to opt for LGPL-2.1 or later, rather than LGPL-2.1-only.
+	   (Here and in mchange-commons-java.)
 	   See https://github.com/swaldman/c3p0/issues/133
 	   Thanks Bernhard E. Reiter!
 	-- Define (in a separate, Java 21, project) a loom virtual-threads based
@@ -34,6 +41,7 @@ c3p0-0.10.0-pre3
 	   See https://github.com/swaldman/c3p0/issues/132
            Thanks marcatl, MichaelMih, Leona Nezvalova!
 	-- Include license files in published source jar.
+	   (Here and in mchange-commons-java.)
 	   See https://github.com/swaldman/c3p0/issues/167
 c3p0-0.10.0-pre2
 	-- Add "Automatic-Module-Name" entry to jar manifest for interoperability with Project Jigsaw / Java 9 modules

build.sc

@@ -65,7 +65,7 @@ object c3p0 extends RootModule with JavaModule with PublishModule {
     }
     override def forkArgs = T{Seq("-Dcom.mchange.v2.log.MLog=com.mchange.v2.log.FallbackMLog")}
   }
-  object bean  extends Gen {}
+  object bean extends Gen {}
 
   object proxy extends Gen {
     override def sources = T { super.sources() :+ PathRef( os.pwd / "src-proxy-interface" ) }
@@ -115,6 +115,8 @@ object c3p0 extends RootModule with JavaModule with PublishModule {
     val bmt = buildModTime()
     val dmt = recursiveDirModTime( T.dest )
     if ( bmt > dmt ) {
+      import java.time.Instant
+      val timestamp = sys.env.get("SOURCE_DATE_EPOCH").map( sde => Instant.ofEpochSecond( sde.toLong ) ).getOrElse( Instant.now )
       val text =
         s"""|package com.mchange.v2.c3p0.subst;
             |
@@ -123,7 +125,7 @@ object c3p0 extends RootModule with JavaModule with PublishModule {
             |    public final static String VERSION    = "${version}";
             |    public final static String DEBUG      = "${Debug}";
             |    public final static String TRACE      = "${Trace}";
-            |    public final static String TIMESTAMP  = "${java.time.Instant.now}";
+            |    public final static String TIMESTAMP  = "${timestamp}";
             |
             |    private C3P0Substitutions()
             |    {}