diff --git a/nspr/lib/ds/Makefile.in b/nspr/lib/ds/Makefile.in
index fa8c783..eff1ac3 100644
--- a/nspr/lib/ds/Makefile.in
+++ b/nspr/lib/ds/Makefile.in
@@ -91,8 +91,8 @@ ECHO = echo
 TINC = $(OBJDIR)/_pl_bld.h
 PROD = $(notdir $(SHARED_LIBRARY))
 NOW = $(MOD_DEPTH)/config/$(OBJDIR)/now
-SH_DATE = $(shell date "+%Y-%m-%d %T")
-SH_NOW = $(shell $(NOW))
+SH_DATE = $(shell date "+%Y-%m-%d %T" --date $(SOURCE_DATE_EPOCH))
+SH_NOW = $(SOURCE_DATE_EPOCH)000000
 
 ifeq ($(NS_USE_GCC)_$(OS_ARCH),_WINNT)
 	SUF = i64
diff --git a/nspr/lib/libc/src/Makefile.in b/nspr/lib/libc/src/Makefile.in
index 9ef2007..2d5db8f 100644
--- a/nspr/lib/libc/src/Makefile.in
+++ b/nspr/lib/libc/src/Makefile.in
@@ -93,8 +93,8 @@ ECHO = echo
 TINC = $(OBJDIR)/_pl_bld.h
 PROD = $(notdir $(SHARED_LIBRARY))
 NOW = $(MOD_DEPTH)/config/$(OBJDIR)/now
-SH_DATE = $(shell date "+%Y-%m-%d %T")
-SH_NOW = $(shell $(NOW))
+SH_DATE = $(shell date "+%Y-%m-%d %T" --date $(SOURCE_DATE_EPOCH))
+SH_NOW = $(SOURCE_DATE_EPOCH)000000
 
 ifeq ($(NS_USE_GCC)_$(OS_ARCH),_WINNT)
 	SUF = i64
diff --git a/nspr/pr/src/Makefile.in b/nspr/pr/src/Makefile.in
index a9e86f5..854c0a9 100644
--- a/nspr/pr/src/Makefile.in
+++ b/nspr/pr/src/Makefile.in
@@ -276,8 +276,8 @@ TINC = $(OBJDIR)/_pr_bld.h
 PROD = $(notdir $(SHARED_LIBRARY))
 
 NOW = $(MOD_DEPTH)/config/$(OBJDIR)/now
-SH_DATE = $(shell date "+%Y-%m-%d %T")
-SH_NOW = $(shell $(NOW))
+SH_DATE = $(shell date "+%Y-%m-%d %T" --date $(SOURCE_DATE_EPOCH))
+SH_NOW = $(SOURCE_DATE_EPOCH)000000
 
 ifeq ($(NS_USE_GCC)_$(OS_ARCH),_WINNT)
 	SUF = i64