bash: use tcmode override

This ensures we pass yocto-check-layers.

Signed-off-by: Christopher Larson <chris_larson@mentor.com>

core/recipes-extended/bash/bash_%.bbappend

@@ -1,4 +1,4 @@
-do_compile_append () {
+do_compile_append_tcmode-external () {
     if [ -e support/bash.pc ] ; then
         sed -i -e 's#-B${gcc_bindir}##' support/bash.pc
     fi