An empty extension for sed -i is not widely available.
* Where it isn't available (eg. macOS's sed) "sed -i -e" will
create a backup file with the "-e" suffix.
* Even GNU sed documentation says it's "not recommended".
This commit deals with it by:
* Replace it with a more appropriate tool (kconfig-tweak)
* Or, specify the extension (.bak)
This works by having the build system look for nuttx/external/Kconfig
to determine whether this directory is present or not. nuttx/external
is gitignored in order to be added by the final user but not to be
commited into the repo. Tipically this will by a symbolic link, just like
apps/external.
Inside external/ a Makefile should be placed with the same structure
than any nuttx/ subdirectory (eg: nuttx/drivers/). The
nuttx/external/Kconfig will be sourced and any options defined there will
appear at the bottom of menuconfig (unless options are conditioned on
menus, in which case they will appear accordingly).
The purpose is to allow arch/board independent code, which for any
reason is not to be upstreamed (propietary, not relevant for mainline,
testing, etc), to be built into the OS during OS building stage. This
way the user does not need to fork the NuttX repo to do so. This feature
complements well with external apps and custom board support.
.d directories are common for holding config and init scripts.
They are being ignored with the global *.d pattern which is meant to
ignore Make dependency files.
Remove boards/arm/sama5/sama5d3-xplained/boot/uImage that can in inadvertantly with a PR merge.
Also, change "/uImage" to just "uImage" in the top-level .gitignore file so that all occurences of uImage will be ignored, not just versions in the nuttx/ top-level directory.
