nativesdk.bbclass: set consistent staging dirs regardless of multilib

*** BLURB HERE ***
The following changes since commit 87d3a9685dd9613e4f6718031d4ebd9344b01c47:

bitbake: parse/ast: ensure saved event handlers really do get restored (2018-08-24 07:53:14 +0100)

are available in the git repository at:

git://git.pokylinux.org/poky-contrib ChenQi/nativesdk-recipe-sysroot
http://git.pokylinux.org/cgit.cgi/poky-contrib/log/?h=ChenQi/nativesdk-recipe-sysroot

Chen Qi (1):
nativesdk.bbclass: set consistent staging dirs regardless of multilib

 meta/classes/nativesdk.bbclass | 5 +++++
 1 file changed, 5 insertions(+)

1.9.1

For now, the RECIPE_SYSROOT of nativesdk recipes is ${WORKDIR}/recipe-sysroot if multilib is disabled and ${WORKDIR}/nativesdk-recipe-sysroot if multilib is enabled. And it's causing chaos. Problems I've met include:
1) 'File Exists' error when doing extend_recipe_sysroot
2) Rebuilding failure about cmake based nativesdk recipes if toggling multilib

In nativesdk.bbclass, We've set MULTILIBS to be "", and we've changed MLPREFIX to be 'nativesdk-', I think we should also set consistent RECIPE_SYSROOT to be ${WORKDIR}/nativesdk-recipe-sysroot.

---
 meta/classes/nativesdk.bbclass | 5 +++++
 1 file changed, 5 insertions(+)

index ab566e9..f3336e5 100644
@@ -12,6 +12,11 @@ MACHINEOVERRIDES = ""
 
 MULTILIBS = ""
 
+# we need consistent staging dir whether or not multilib is enabled
+STAGING_DIR_HOST = "${WORKDIR}/nativesdk-recipe-sysroot"
+STAGING_DIR_TARGET = "${WORKDIR}/nativesdk-recipe-sysroot"
+RECIPE_SYSROOT = "${WORKDIR}/nativesdk-recipe-sysroot"
+
 #
 # Update PACKAGE_ARCH and PACKAGE_ARCHS
 #

1.9.1