[PATCH] dtc: improve reproducibility

["Oleksiy Obitotskyy" <oobitots@cisco.com>]

Makefile override CFLAGS, so -fmacro/debug-prefix-map
optiions was omitted and binaries contains absolute
patch to sources.

Signed-off-by: Oleksiy Obitotskyy <oobitots@cisco.com>
---
 meta/recipes-kernel/dtc/dtc.inc               | 10 +++++-
 ...-Makefile-to-add-CFLAGS-not-override.patch | 36 +++++++++++++++++++
 2 files changed, 45 insertions(+), 1 deletion(-)
 create mode 100644 meta/recipes-kernel/dtc/dtc/0001-dtc-Fix-Makefile-to-add-CFLAGS-not-override.patch

diff --git a/meta/recipes-kernel/dtc/dtc.inc b/meta/recipes-kernel/dtc/dtc.inc
index 0650e3c82e..59badd4951 100644
--- a/meta/recipes-kernel/dtc/dtc.inc
+++ b/meta/recipes-kernel/dtc/dtc.inc
@@ -8,6 +8,14 @@ DEPENDS = "flex-native bison-native"
 SRC_URI = "git://git.kernel.org/pub/scm/utils/dtc/dtc.git \
            file://make_install.patch \
            "
+
+def get_reproducibility_patches(d):
+     if bb.data.inherits_class("reproducible_build", d):
+        return "file://0001-dtc-Fix-Makefile-to-add-CFLAGS-not-override.patch"
+     return ""
+
+SRC_URI += "${@get_reproducibility_patches(d)}"
+
 UPSTREAM_CHECK_GITTAGREGEX = "v(?P<pver>\d+(\.\d+)+)"
 
 EXTRA_OEMAKE='NO_PYTHON=1 PREFIX="${prefix}" LIBDIR="${libdir}" DESTDIR="${D}"'
diff --git a/meta/recipes-kernel/dtc/dtc/0001-dtc-Fix-Makefile-to-add-CFLAGS-not-override.patch b/meta/recipes-kernel/dtc/dtc/0001-dtc-Fix-Makefile-to-add-CFLAGS-not-override.patch
new file mode 100644
index 0000000000..6ac83929b9
--- /dev/null
+++ b/meta/recipes-kernel/dtc/dtc/0001-dtc-Fix-Makefile-to-add-CFLAGS-not-override.patch
@@ -0,0 +1,36 @@
+From d684b031967ee7055d5719476ef578fe2c37401c Mon Sep 17 00:00:00 2001
+From: Oleksiy Obitotskyy <oobitots@cisco.com>
+Date: Thu, 24 Sep 2020 05:12:42 -0700
+Subject: [PATCH] dtc: Fix Makefile to add CFLAGS not override
+
+Makefile override CFLAGS not extend them, so some of them
+missing. Sources builds out of kernel tree and probably not all
+options could be used (?). We need at least -fmacro-prefix-map/
+debug-prefix-map to eliminate absolute path in binaries.
+
+Upstream-Status: Pending
+Signed-off-by: Oleksiy Obitotskyy <oobitots@cisco.com>
+---
+ Makefile | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/Makefile b/Makefile
+index f729bf6..bb51a92 100644
+--- a/Makefile
++++ b/Makefile
+@@ -16,10 +16,10 @@ EXTRAVERSION =
+ LOCAL_VERSION =
+ CONFIG_LOCALVERSION =
+ 
+-CPPFLAGS = -I libfdt -I .
++CPPFLAGS += -I libfdt -I .
+ WARNINGS = -Wall -Wpointer-arith -Wcast-qual -Wnested-externs \
+ 	-Wstrict-prototypes -Wmissing-prototypes -Wredundant-decls -Wshadow
+-CFLAGS = -g -Os $(SHAREDLIB_CFLAGS) -Werror $(WARNINGS) $(EXTRA_CFLAGS)
++CFLAGS += -g -Os $(SHAREDLIB_CFLAGS) -Werror $(WARNINGS) $(EXTRA_CFLAGS)
+ 
+ BISON = bison
+ LEX = flex
+-- 
+2.19.0.dirty
+
-- 
2.26.2.Cisco