[Buildroot] [git commit branch/2018.02.x] linux: Make dtc install step more reliable

[Peter Korsgaard]

commit: https://git.buildroot.net/buildroot/commit/?id=1353c0c8e26a190c27238360d7a917b945f02d52
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/2018.02.x

Checking for the existence of the dtc binary built by the
non-dependent dtc package may cause instable behaviour when giving more
freedom on the order of how the packages are built (parallelization).

In addidion, when moving to per-package host/target method, the check
would always trigger in the isolated host, leading to linux-dtc always
being installed as dtc.
This in turn may lead to undesired overwriting of the real host-dtc binary
when finally assembling the global host dir.

Thus rework the linux-dtc install condition to be defined by configuration
rather than compile time order.

Signed-off-by: Andreas Naumann <anaumann at ultratronik.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
(cherry picked from commit 860906ee05fad3fe503786ec7c656ea0f25851fc)
Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
---
 linux/linux.mk | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/linux/linux.mk b/linux/linux.mk
index f69aeb48bb..38a67edcd1 100644
--- a/linux/linux.mk
+++ b/linux/linux.mk
@@ -416,9 +416,7 @@ define LINUX_INSTALL_HOST_TOOLS
 	# Installing dtc (device tree compiler) as host tool, if selected
 	if grep -q "CONFIG_DTC=y" $(@D)/.config; then	\
 		$(INSTALL) -D -m 0755 $(@D)/scripts/dtc/dtc $(HOST_DIR)/bin/linux-dtc ;	\
-		if [ ! -e $(HOST_DIR)/bin/dtc ]; then	\
-			ln -sf linux-dtc $(HOST_DIR)/bin/dtc ;	\
-		fi	\
+		$(if $(BR2_PACKAGE_HOST_DTC),,ln -sf linux-dtc $(HOST_DIR)/bin/dtc;) \
 	fi
 endef