populate_sdk: Handle OLDEST_KERNEL

Add a check to the SDK so that it only runs on systems with kernel versions
it supports.

[YOCTO #6856]

(From OE-Core rev: b4caa8085aa15674162ff5135b13409998db9510)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/populate_sdk_base.bbclass

@@ -126,6 +126,7 @@ EOF
 	# substitute variables
 	sed -i -e 's#@SDK_ARCH@#${SDK_ARCH}#g' \
 		-e 's#@SDKPATH@#${SDKPATH}#g' \
+		-e 's#@OLDEST_KERNEL@#${OLDEST_KERNEL}#g' \
 		-e 's#@REAL_MULTIMACH_TARGET_SYS@#${REAL_MULTIMACH_TARGET_SYS}#g' \
 		-e '/@SDK_POST_INSTALL_COMMAND@/d' \
 		${SDK_DEPLOY}/${TOOLCHAIN_OUTPUTNAME}.sh

meta/files/toolchain-shar-template.sh

@@ -3,6 +3,20 @@
 INST_ARCH=$(uname -m | sed -e "s/i[3-6]86/ix86/" -e "s/x86[-_]64/x86_64/")
 SDK_ARCH=$(echo @SDK_ARCH@ | sed -e "s/i[3-6]86/ix86/" -e "s/x86[-_]64/x86_64/")
 
+verlte () {
+	[  "$1" = "`printf "$1\n$2" | sort -V | head -n1`" ]
+}
+
+verlt() {
+	[ "$1" = "$2" ] && return 1 || verlte $1 $2
+}
+
+verlt `uname -r` @OLDEST_KERNEL@
+if [ $? = 0 ]; then
+	echo "Error: The SDK needs a kernel > @OLDEST_KERNEL@"
+	exit 1
+fi
+
 if [ "$INST_ARCH" != "$SDK_ARCH" ]; then
 	# Allow for installation of ix86 SDK on x86_64 host
 	if [ "$INST_ARCH" != x86_64 -o "$SDK_ARCH" != ix86 ]; then