meta-toolchain: Update the way ld.so.cache is handled

Fix the library search path so that libs in the toolchain in /opt/
have priority over those in base system but ones from the base system
can still be found.

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

meta/classes/toolchain-scripts.bbclass

@@ -6,6 +6,10 @@ toolchain_create_sdk_env_script () {
 	script=${SDK_OUTPUT}/${SDKPATH}/environment-setup-${MULTIMACH_TARGET_SYS}
 	rm -f $script
 	touch $script
+	echo 'if [ ! -e ${SDKPATHNATIVE}/etc/ld.so.cache ]; then' >> $script
+	echo '    echo "Please run ${SDKPATH}/postinstall as root before using the toolchain"'  >> $script
+	echo '    exit 1' >> $script
+	echo 'fi' >> $script
 	echo 'export PATH=${SDKPATHNATIVE}${bindir_nativesdk}:${SDKPATHNATIVE}${bindir_nativesdk}/${MULTIMACH_TARGET_SYS}:$PATH' >> $script
 	echo 'export PKG_CONFIG_SYSROOT_DIR=${SDKTARGETSYSROOT}' >> $script
 	echo 'export PKG_CONFIG_PATH=${SDKTARGETSYSROOT}${libdir}/pkgconfig' >> $script