[source] include/kernel: Switch to git download method

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/9a08c0ba807b7e362de5afe78140f3bb4188746c

commit 9a08c0ba807b7e362de5afe78140f3bb4188746c
Author: Florian Fainelli <f.fainelli at gmail.com>
AuthorDate: Wed Nov 9 09:34:18 2016 -0800

    include/kernel: Switch to git download method
    
    Utilize the existing git download logic from include/download.mk and migrate
    the kernel download over to it. This avoids repeatedly cloning kernel sources
    after a make target/linux/clean for instance.
    
    Signed-off-by: Florian Fainelli <f.fainelli at gmail.com>
    Signed-off-by: Felix Fietkau <nbd at nbd.name> [fix build error]
---
 include/kernel-build.mk    | 19 +++++++++++++++++++
 include/kernel-defaults.mk | 11 +----------
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/include/kernel-build.mk b/include/kernel-build.mk
index 04878f8..062c458 100644
--- a/include/kernel-build.mk
+++ b/include/kernel-build.mk
@@ -46,6 +46,24 @@ define Download/kernel
   MD5SUM:=$(LINUX_KERNEL_MD5SUM)
 endef
 
+KERNEL_GIT_OPTS:=
+ifneq ($(strip $(CONFIG_KERNEL_GIT_LOCAL_REPOSITORY)),"")
+  KERNEL_GIT_OPTS+=--reference $(CONFIG_KERNEL_GIT_LOCAL_REPOSITORY)
+endif
+
+ifneq ($(strip $(CONFIG_KERNEL_GIT_BRANCH)),"")
+  KERNEL_GIT_OPTS+=--branch $(CONFIG_KERNEL_GIT_BRANCH)
+endif
+
+define Download/git-kernel
+  URL:=$(call qstrip,$(CONFIG_KERNEL_GIT_CLONE_URI))
+  PROTO:=git
+  VERSION:=$(CONFIG_KERNEL_GIT_BRANCH)
+  FILE:=$(LINUX_SOURCE)
+  SUBDIR:=linux-$(KERNEL_PATCHVER)
+  OPTS:=$(KERNEL_GIT_OPTS)
+endef
+
 ifdef CONFIG_COLLECT_KERNEL_DEBUG
   define Kernel/CollectDebug
 	rm -rf $(KERNEL_BUILD_DIR)/debug
@@ -73,6 +91,7 @@ endif
 define BuildKernel
   $(if $(QUILT),$(Build/Quilt))
   $(if $(LINUX_SITE),$(call Download,kernel))
+  $(if $(call qstrip,$(CONFIG_KERNEL_GIT_CLONE_URI)),$(call Download,git-kernel))
 
   .NOTPARALLEL:
 
diff --git a/include/kernel-defaults.mk b/include/kernel-defaults.mk
index eff4700..a17b489 100644
--- a/include/kernel-defaults.mk
+++ b/include/kernel-defaults.mk
@@ -49,15 +49,6 @@ export HOST_EXTRACFLAGS=-I$(STAGING_DIR_HOST)/include
 # defined in quilt.mk
 Kernel/Patch:=$(Kernel/Patch/Default)
 
-KERNEL_GIT_OPTS:=
-ifneq ($(strip $(CONFIG_KERNEL_GIT_LOCAL_REPOSITORY)),"")
-  KERNEL_GIT_OPTS+=--reference $(CONFIG_KERNEL_GIT_LOCAL_REPOSITORY)
-endif
-
-ifneq ($(strip $(CONFIG_KERNEL_GIT_BRANCH)),"")
-  KERNEL_GIT_OPTS+=--branch $(CONFIG_KERNEL_GIT_BRANCH)
-endif
-
 ifeq ($(strip $(CONFIG_EXTERNAL_KERNEL_TREE)),"")
   ifeq ($(strip $(CONFIG_KERNEL_GIT_CLONE_URI)),"")
     define Kernel/Prepare/Default
@@ -67,7 +58,7 @@ ifeq ($(strip $(CONFIG_EXTERNAL_KERNEL_TREE)),"")
     endef
   else
     define Kernel/Prepare/Default
-	git clone $(KERNEL_GIT_OPTS) $(CONFIG_KERNEL_GIT_CLONE_URI) $(LINUX_DIR)
+	xzcat $(DL_DIR)/$(LINUX_SOURCE) | $(TAR) -C $(KERNEL_BUILD_DIR) $(TAR_OPTIONS)
     endef
   endif
 else