[PATCH] toolchain-scripts: Allow the CONFIGSITE_CACHE variable to be overridden

[Richard Purdie <richard.purdie@linuxfoundation.org>]

In multilib and baremetal configurations, this variable can cause a variety of
problems due to the use of TCLIBC. At least allowing it to be overriden
is a start and allows various configurations to avoid the issue.

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

diff --git a/meta/classes/toolchain-scripts.bbclass b/meta/classes/toolchain-scripts.bbclass
index 0e849e4..8809ec2 100644
--- a/meta/classes/toolchain-scripts.bbclass
+++ b/meta/classes/toolchain-scripts.bbclass
@@ -98,7 +98,7 @@ EOF
 #we get the cached site config in the runtime
 TOOLCHAIN_CONFIGSITE_NOCACHE = "${@siteinfo_get_files(d, True)}"
 TOOLCHAIN_CONFIGSITE_SYSROOTCACHE = "${STAGING_DIR}/${MLPREFIX}${MACHINE}/${target_datadir}/${TARGET_SYS}_config_site.d"
-TOOLCHAIN_NEED_CONFIGSITE_CACHE = "${TCLIBC} ncurses"
+TOOLCHAIN_NEED_CONFIGSITE_CACHE ??= "${TCLIBC} ncurses"
 
 #This function create a site config file
 toolchain_create_sdk_siteconfig () {