diff --git a/lazarus.changes b/lazarus.changes
index c712fd1..a05073f 100644
--- a/lazarus.changes
+++ b/lazarus.changes
@@ -1,3 +1,8 @@
+-------------------------------------------------------------------
+Tue May  2 04:56:49 UTC 2017 - bwiedemann@suse.com
+
+- Make build more reproducible
+
 -------------------------------------------------------------------
 Tue Feb  7 18:31:12 UTC 2017 - mailaender@opensuse.org
 
diff --git a/lazarus.spec b/lazarus.spec
index 314c338..c71e861 100644
--- a/lazarus.spec
+++ b/lazarus.spec
@@ -106,6 +106,12 @@ dos2unix examples/trayicon/wndtray.*
 
 # fix rpmlint error "spurious-executable-perm"
 chmod 644 docs/booth/ProdProgEntwMitOpenSourceSystems2007.odp
+if [[ $SOURCE_DATE_EPOCH ]] ; then
+  datestr=$(date -u "-d@$SOURCE_DATE_EPOCH" +%Y/%m/%d)
+  sed -i -e "s!{\$I %%date%%}!'$datestr'!" \
+    ide/ideinfodlg.pas ide/aboutfrm.pas ide/idefpcinfo.pas
+  touch -d@$SOURCE_DATE_EPOCH ide/ideinfodlg.pas ide/aboutfrm.pas ide/idefpcinfo.pas # reset source timestamps because they are embedded in compiled files
+fi
 
 %build
 # Don't use -gs (use explicitly "stabs" debuginfo) for compiling lhelp but -g (use the default debuginfo type "dwarf") as in the rest of package's Makefiles