[Buildroot] [git commit] Makefile: be careful what we remove from saved defconfig

[Thomas Petazzoni]

commit: https://git.buildroot.net/buildroot/commit/?id=1a7873ec986c817fdd22cc2d9096d9482fee4381
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/master

When we savedefconfig, we remove BR2_DEFCONFIG (f71a621d91e, savedefconfig:
Remove BR2_DEFCONFIG from saved defconfig file) and BR2_DL_DIR (36edacce9c2,
Makefile: exclude BR2_DL_DIR from savedefconfig), because their meaning
is only valid locally.

However, we were not careful to really match the exact variables, so we
could match arbitrary options.

For example, these config options would all be dropped:

    BR2_DEFCONFIG="toto"
    BR2_DL_DIR="titi"
    BR2_PACKAGE_SABR2_DEFCONFIG="tutu"
    BR2_PACKAGE_SABR2_DL_DIR=y

While the first two are indeed the ones we want to drop, the last two
are options (whatever their meaning or how poorly named they are) of the
hypothetical 'sabr2' package, and we want to keep those in a defconfig.

When cleaning the just-saved defconfig, be sure to anchor the patterns to
the beginning of the line.

Signed-off-by: Yann E. MORIN <yann.morin.1998 at free.fr>
Cc: Sven Oliver Moll <buildroot at svol.li>
Cc: Herve Codina <Herve.CODINA at celad.com>
Acked-by: Herve Codina <Herve.CODINA at celad.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
---
 Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index d1d19d8f40..d4751e278e 100644
--- a/Makefile
+++ b/Makefile
@@ -1027,8 +1027,8 @@ savedefconfig: $(BUILD_DIR)/buildroot-config/conf outputmakefile
 	@$(COMMON_CONFIG_ENV) $< \
 		--savedefconfig=$(if $(DEFCONFIG),$(DEFCONFIG),$(CONFIG_DIR)/defconfig) \
 		$(CONFIG_CONFIG_IN)
-	@$(SED) '/BR2_DEFCONFIG=/d' \
-		-e '/BR2_DL_DIR=/d' \
+	@$(SED) '/^BR2_DEFCONFIG=/d' \
+		-e '/^BR2_DL_DIR=/d' \
 		$(if $(DEFCONFIG),$(DEFCONFIG),$(CONFIG_DIR)/defconfig)
 
 .PHONY: defconfig savedefconfig update-defconfig