gcc-common: Exclude AVAILTUNES from sstate checksums

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

AVAILTUNES is only used as a sanity check, we don't need to
include it in the sstate checksum in this case. If included
it can cause problems when switching machines with a common
package architecture.

[YOCTO #3667]

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
---
diff --git a/meta/recipes-devtools/gcc/gcc-common.inc b/meta/recipes-devtools/gcc/gcc-common.inc
index 6b61800..a32646f 100644
--- a/meta/recipes-devtools/gcc/gcc-common.inc
+++ b/meta/recipes-devtools/gcc/gcc-common.inc
@@ -58,6 +58,8 @@ def get_tune_parameters(tune, d):
     retdict['package_extra_archs'] = localdata.getVar('PACKAGE_EXTRA_ARCHS', True)
     return retdict
 
+get_tune_parameters[vardepsexclude] = "AVAILTUNES"
+
 # We really need HOST_SYS here for some packages and TARGET_SYS for others.
 # For now, libgcc is most important so we fix for that - RP.
 SHLIBSDIR = "${STAGING_DIR_TARGET}/shlibs"