+Many modules are provided dual-license, either GPL or LGPL at your
+option. The headers of files in the lib directory (e.g., lib/error.c)
+state GPL for convenience, since the bulk of current gnulib users are
+GPL'd programs. But the files in the modules directory (e.g.,
+modules/error) state the true license of each file, and when you use
+'gnulib-tool --lgpl --import <modules>', gnulib-tool either rewrites
+the files to have an LGPL header as part of copying them from gnulib
+to your project directory, or fails because the modules you requested
+were not licensed under LGPL.
+