busybox: disable build timestamps for reproducible builds

Busybox includes some information about the build environment in its
binary. For BR2_REPRODUCIBLE, remove that information.

Signed-off-by: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
Signed-off-by: Jérôme Pouiller <jezz@sysmic.org>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/busybox/busybox.mk

@@ -36,6 +36,12 @@ BUSYBOX_MAKE_ENV = \
 	$(TARGET_MAKE_ENV) \
 	CFLAGS="$(BUSYBOX_CFLAGS)" \
 	CFLAGS_busybox="$(BUSYBOX_CFLAGS_busybox)"
+
+ifeq ($(BR2_REPRODUCIBLE),y)
+BUSYBOX_MAKE_ENV += \
+	KCONFIG_NOTIMESTAMP=1
+endif
+
 BUSYBOX_MAKE_OPTS = \
 	CC="$(TARGET_CC)" \
 	ARCH=$(KERNEL_ARCH) \