Add legal info. Fixes #12.

legal-info/README

@@ -0,0 +1,42 @@
+Most of the packages that were used by Buildroot to produce the image files,
+including Buildroot itself, have open-source licenses. It is your
+responsibility to comply to the requirements of these licenses.
+To make this easier for you, Buildroot collected in this directory some
+material you may need to get it done.
+
+This material is composed of the following items.
+ * The scripts used to control compilation of the packages and the generation
+   of image files, i.e. the Buildroot sources.
+   Note: this has not been saved due to technical limitations, you must
+   collect it manually.
+ * The Buildroot configuration file; this has been saved in buildroot.config.
+ * The toolchain (cross-compiler and related tools) used to generate all the
+   compiled programs.
+   Note: this may have not been saved due to technical limitations, you may
+   need to collect it manually.
+ * The original source code for target packages in the 'sources/'
+   subdirectory and for host packages in the 'host-sources/' subdirectory
+   (except for the non-redistributable packages, which have not been
+   saved). Patches that were applied are also saved, along with a file
+   named 'series' that lists the patches in the order they were
+   applied. Patches are under the same license as the files that they
+   modify in the original package.
+   Note: Buildroot applies additional patches to Libtool scripts of
+   autotools-based packages. These patches can be found under
+   support/libtool in the Buildroot source and, due to technical
+   limitations, are not saved with the package sources. You may need
+   to collect them manually.
+ * Two manifest files listing the configured packages and related
+   information: 'manifest.csv' for target packages and 'host-manifest.csv'
+   for host packages.
+ * The license text of the packages, in the 'licenses/' and
+   'host-licenses/' subdirectories for target and host packages
+   respectively.
+
+Due to technical limitations or lack of license definition in the package
+makefile, some of the material listed above could not been saved, as the
+following list details.
+
+WARNING: the Buildroot source code has not been saved
+WARNING: gcc-final-8.4.0: cannot save license (HOST_GCC_FINAL_LICENSE_FILES not defined)
+WARNING: gcc-initial-8.4.0: cannot save license (HOST_GCC_INITIAL_LICENSE_FILES not defined)