[gnome-continuous-yocto/gnomeostree-3.28-rocko: 7344/8267] kernel.bbclass: external toolchain fix

[Emmanuele Bassi <ebassi src gnome org>]

commit 06ff0a9c8a26e394d65cf00ec6b9f1d1958c7fcf
Author: Juro Bystricky <juro bystricky intel com>
Date:   Sat Aug 19 09:41:35 2017 -0700

    kernel.bbclass: external toolchain fix
    
    Refactor get_cc_option so it is simpler and also does not fail
    when using external toolchain.
    
    (From OE-Core rev: d4564ee59df907d1e01a3610ac88a35f9a78c1ce)
    
    Signed-off-by: Juro Bystricky <juro bystricky intel com>
    Signed-off-by: Richard Purdie <richard purdie linuxfoundation org>

 meta/classes/kernel.bbclass |    7 ++-----
 1 files changed, 2 insertions(+), 5 deletions(-)
---
diff --git a/meta/classes/kernel.bbclass b/meta/classes/kernel.bbclass
index 2a76554..3cc0432 100644
--- a/meta/classes/kernel.bbclass
+++ b/meta/classes/kernel.bbclass
@@ -259,12 +259,9 @@ get_cc_option () {
                # Check if KERNEL_CC supports the option "file-prefix-map".
                # This option allows us to build images with __FILE__ values that do not
                # contain the host build path.
-               cc_option_supported=`${KERNEL_CC} -Q --help=joined | grep ffile-prefix-map`
-               cc_extra=""
-               if [ $cc_option_supported = "-ffile-prefix-map=<old=new>" ]; then
-                       cc_extra=-ffile-prefix-map=${S}=/kernel-source/
+               if ${KERNEL_CC} -Q --help=joined | grep -q "\-ffile-prefix-map=<old=new>"; then
+                       echo "-ffile-prefix-map=${S}=/kernel-source/"
                fi
-               echo $cc_extra
 }
 
 kernel_do_compile() {