build: Honor $SOURCE_DATE_EPOCH for the recorded timestamp.

Reported by Jan Nieuwenhuizen <janneke@gnu.org>
at <https://debbugs.gnu.org/cgi/bugreport.cgi?bug=20272#36>.

* libguile/Makefile.am (libpath.h): Honor 'SOURCE_DATE_EPOCH'.

diff --git a/libguile/Makefile.am b/libguile/Makefile.am
index fa602201cac1e8ad38f6b14e135e7bd3f1203eab..07466069fbe05c16d7340998baa4d87e6164e6b7 100644 (file)
--- a/libguile/Makefile.am
+++ b/libguile/Makefile.am
@@ -740,7 +740,8 @@ libpath.h: $(srcdir)/Makefile.in  $(top_builddir)/config.status
                >> libpath.tmp
        @echo ' { "LIBS",          "@GUILE_LIBS@" }, \' >> libpath.tmp
        @echo ' { "CFLAGS",        "@GUILE_CFLAGS@" }, \' >> libpath.tmp
-       @echo ' { "buildstamp",    "'`date -u +'%Y-%m-%d %T'`'" }, \' >> libpath.tmp
+       @BUILD_DATE="$${SOURCE_DATE_EPOCH:-`date '+%s'`}" ; \
+        echo ' { "buildstamp",    "'`date -u +'%Y-%m-%d %T' -d @$$BUILD_DATE`'" }, \' >> libpath.tmp
        @echo '}' >> libpath.tmp
        $(AM_V_GEN)mv libpath.tmp libpath.h