File reproducible.patch of Package pw3270

https://github.com/PerryWerneck/pw3270/pull/50

commit cb81bc57072be6f0645defd212399b04dc1d6e63
Author: Bernhard M. Wiedemann <bwiedemann@suse.de>
Date:   Sun Mar 26 15:45:42 2023 +0200

    Allow to override build date with SOURCE_DATE_EPOCH
    
    in order to make builds reproducible.
    See https://reproducible-builds.org/ for why this is good
    and https://reproducible-builds.org/specs/source-date-epoch/
    for the definition of this variable.
    
    This date call works with different implementations of date.
    
    Also use UTC to be independent of timezone.
    
    This patch was done while working on reproducible builds for openSUSE.

diff --git a/configure.ac b/configure.ac
index 2157c7c5..86b319c2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -119,7 +119,9 @@ case "$host" in
 
 esac
 
-app_release_date=$(date +%Y-%m-%d)
+DATE_FMT="+%Y-%m-%d"
+SOURCE_DATE_EPOCH="${SOURCE_DATE_EPOCH:-$(date +%s)}"
+app_release_date=$(date -u -d "@$SOURCE_DATE_EPOCH" "$DATE_FMT" 2>/dev/null || date -u -r "$SOURCE_DATE_EPOCH" "$DATE_FMT" 2>/dev/null || date -u "$DATE_FMT")
 AC_SUBST(RELEASE_DATE,$app_release_date)
 AC_SUBST(OSNAME,$app_cv_osname)
 AC_SUBST(RLS_LDFLAGS,$app_rls_ldflags)