uboot-config: Fix devtool modify

Fix a problem with `devtool modify` as suggested by Marcus Flyckt on
the mailing list:
```
    I encountered an issue with `do_config` when using `devtool modify`
    on `u-boot-imx`.

    ```
    [...]
    | cp: cannot stat '[...]/u-boot-imx/2024.04/build/imx8mp_wl400s_defconfig/.config': No such file or directory
    | WARNING: exit code 1 from a shell command.
    ERROR: Task ([...]/sources/poky/../meta-freescale/recipes-bsp/u-boot/u-boot-imx_2024.04.bb:do_configure) failed with exit code '1'
    NOTE: Tasks Summary: Attempted 963 tasks of which 962 didn't need to be rerun and 1 failed.
    Summary: 1 task failed:
      [...]/sources/poky/../meta-freescale/recipes-bsp/u-boot/u-boot-imx_2024.04.bb:do_configure
    Summary: There was 1 ERROR message, returning a non-zero exit code
    ```

    The issue seems to originate from the following lines in
    `workspace/appends/u-boot-imx_2024.04.bbappend`:

    ```
    do_configure:append() {
        if [ ${@oe.types.boolean(d.getVar("KCONFIG_CONFIG_ENABLE_MENUCONFIG"))} = True ]; then
            cp ${KCONFIG_CONFIG_ROOTDIR}/.config ${S}/.config.baseline
            ln -sfT ${KCONFIG_CONFIG_ROOTDIR}/.config ${S}/.config.new
        fi
    }
    ```

    For some reason `KCONFIG_CONFIG_ROOTDIR` does not point to the
    correct directory. It gets its value in `uboot-config.bbclass`:

    ```
    if len(ubootconfig) == 1:
                    d.setVar('KCONFIG_CONFIG_ROOTDIR', os.path.join(d.getVar("B"), d.getVar("UBOOT_MACHINE").strip()))
    ```

    So the main issue is that B gets expanded in this expression, and
    then later B gets changed by `externalsrc.bbclass`.
    `d.getVar("B", False)` does not solve the issue, however the
    proposed change does.
```
- https://lists.yoctoproject.org/g/yocto/topic/109254298#msg64152]

Fixes [YOCTO #15603]

Suggested-by: Marcus Flyckt <marcus.flyckt@gmail.com>
(From OE-Core rev: 57b21065a25100c31515b32fd7c77bde3355d684)

Signed-off-by: Tom Hochstein <tom.hochstein@oss.nxp.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/meta/classes-recipe/uboot-config.bbclass b/meta/classes-recipe/uboot-config.bbclass
index bf21961977..74992182c3 100644
--- a/meta/classes-recipe/uboot-config.bbclass
+++ b/meta/classes-recipe/uboot-config.bbclass
@@ -144,7 +144,7 @@ python () {
             # Ensure the uboot specific menuconfig settings do not leak into other recipes
             if 'u-boot' in recipename:
                 if len(ubootconfig) == 1:
-                    d.setVar('KCONFIG_CONFIG_ROOTDIR', os.path.join(d.getVar("B"), d.getVar("UBOOT_MACHINE").strip()))
+                    d.setVar('KCONFIG_CONFIG_ROOTDIR', os.path.join("${B}", d.getVar("UBOOT_MACHINE").strip()))
                 else:
                     # Disable menuconfig for multiple configs
                     d.setVar('KCONFIG_CONFIG_ENABLE_MENUCONFIG', "false")