git: 8a3537aaf7c1 - main - Makefile.inc1: Make package timestamps reproducible by default

The branch main has been updated by emaste:

URL: https://cgit.FreeBSD.org/src/commit/?id=8a3537aaf7c19f7331fcc160ab42e36fc79e408a

commit 8a3537aaf7c19f7331fcc160ab42e36fc79e408a
Author:     Ed Maste <emaste@FreeBSD.org>
AuthorDate: 2025-02-27 13:17:11 +0000
Commit:     Ed Maste <emaste@FreeBSD.org>
CommitDate: 2025-02-28 15:11:52 +0000

    Makefile.inc1: Make package timestamps reproducible by default
    
    Set package archive timestamps based on most recent source commit
    timestamp (approach suggested by bapt).
    
    I'd like to include git metadata in a file included in src tarballs, so
    that the build is reproducible (including the hash shown in uname etc.)
    outside of a git checkout.  There are still details to be sorted out to
    do that, so this is an interim step to improve reproducibility.
    
    Reviewed by:    bapt
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D49165
---
 Makefile.inc1 | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Makefile.inc1 b/Makefile.inc1
index c9a4fee236aa..f51fe7d3b119 100644
--- a/Makefile.inc1
+++ b/Makefile.inc1
@@ -597,8 +597,12 @@ PKG_VERSION:=	${_PKG_REVISION}${EXTRA_REVISION:C/[[:space:]]//g}
 .endif	# !defined(PKG_VERSION)
 
 .if !defined(PKG_TIMESTAMP)
+.if !empty(GIT_CMD) && exists(${GIT_CMD}) && exists(${SRCDIR}/.git)
+SOURCE_DATE_EPOCH!=	${GIT_CMD} -C ${SRCDIR} show -s --format=%ct HEAD
+.else
 TIMEEPOCHNOW=		%s
 SOURCE_DATE_EPOCH=	${TIMEEPOCHNOW:gmtime}
+.endif
 .else
 SOURCE_DATE_EPOCH=	${PKG_TIMESTAMP}
 .endif