diff --git a/GNUmakefile b/GNUmakefile
index d925dfe4..c06b91ab 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -24,7 +24,11 @@ HAVE_WIN := 0
 ifeq ($(shell test -d .git && which git > /dev/null && echo 1),1)
 export SOURCE_DATE_EPOCH=$(shell git log -1 --pretty=%ct)
 export TZ=UTC
+else
+export SOURCE_DATE_EPOCH=1
+export TZ=UTC
 endif
+$(info SOURCE_DATE_EPOCH=$(SOURCE_DATE_EPOCH))
 
 ifeq ($(UNAME_S),Darwin)
 BUILD_TYPES := macosdebug macosrelease iosdebug iosrelease iossimdebug iossimrelease