先看文档说明：
rebuilding-packages.txt
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=== Understanding how to rebuild packages
One of the most common questions asked by Buildroot users is how to
rebuild a given package or how to remove a package without rebuilding
everything from scratch.
Removing a package is unsupported by Buildroot without
rebuilding from scratch. This is because Buildroot doesn’t keep track
of which package installs what files in the +output/staging+ and
+output/target+ directories, or which package would be compiled differently
depending on the availability of another package.
The easiest way to rebuild a single package from scratch is to remove
its build directory in +output/build+. Buildroot will then re-extract,
re-configure, re-compile and re-install this package from scratch. You
can ask buildroot to do this with the +make
On the other hand, if you only want to restart the build process of a
package from its compilation step, you can run +make
restart the compilation and installation of the package, but not from
scratch: it basically re-executes +make+ and +make install+
inside the package, so it will only rebuild files that changed.
If you want to restart the build process of a package from its
configuration step, you can run +make
by +make+ or +make
compilation and installation of the package.
Internally, Buildroot creates so-called stamp files to keep track of
which build steps have been completed for each package. They are
stored in the package build directory,
+output/build/
+.stamp_
these stamp files to force Buildroot to restart a specific set of
steps of a package build process.
Further details about package special make targets are explained in
xref:pkg-build-steps[].
进入 buildroot/output/build/”要删除的package名称”
删除 .stamp_built和.stamp_target_installed
