[OE-core] [PATCH] libjpeg-turbo: improve reproducibility

[Juro Bystricky]

Build date ends up embbedded in binary images, breaking reproducibility
of jpeg-tools and libturbojpeg. To enable reproducible builds, build date can be
specified during configuration, via "--with_build_date=<date>".
If SOURCE_DATE_EPOCH is specified we configure libjpeg-turbo with this value as
build date. Although the build date is a generic string, we keep it in the same
format YYYYMMDD.

[YOCTO #12526]

Signed-off-by: Juro Bystricky <juro.bystricky at intel.com>
---
 meta/recipes-graphics/jpeg/libjpeg-turbo_1.5.3.bb | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/meta/recipes-graphics/jpeg/libjpeg-turbo_1.5.3.bb b/meta/recipes-graphics/jpeg/libjpeg-turbo_1.5.3.bb
index 8809f2c..50a5ae0 100644
--- a/meta/recipes-graphics/jpeg/libjpeg-turbo_1.5.3.bb
+++ b/meta/recipes-graphics/jpeg/libjpeg-turbo_1.5.3.bb
@@ -40,6 +40,14 @@ EXTRA_OECONF_append_class-target = " ${@bb.utils.contains("MIPSPKGSFX_FPU", "-nf
 EXTRA_OECONF_append_class-target_powerpc = " ${@bb.utils.contains("TUNE_FEATURES", "altivec", "", "--without-simd", d)}"
 EXTRA_OECONF_append_class-target_powerpc64 = " ${@bb.utils.contains("TUNE_FEATURES", "altivec", "", "--without-simd", d)}"
 
+def get_build_time(d):
+    if d.getVar('SOURCE_DATE_EPOCH') != None:
+        import datetime
+        return " --with-build-date="+ datetime.datetime.fromtimestamp(float(d.getVar('SOURCE_DATE_EPOCH'))).strftime("%Y%m%d")
+    return ""
+
+EXTRA_OECONF_append_class-target = "${@get_build_time(d)}"
+
 PACKAGES =+ "jpeg-tools libturbojpeg"
 
 DESCRIPTION_jpeg-tools = "The jpeg-tools package includes client programs to access libjpeg functionality.  These tools allow for the compression, decompression, transformation and display of JPEG files and benchmarking of the libjpeg library."
-- 
2.7.4