+Some modules also provide other files necessary
+for building. These files are copied into the directory specified
+by @samp{AC_CONFIG_AUX_DIR} in @file{configure.ac} or by the
+@code{--aux-dir=DIRECTORY} option. If neither is specified, the
+current directory is assumed.
+
+@code{gnulib-tool} can make symbolic links instead
+of copying the source files. Use the @code{--symbolic}
+(or @code{-s} for short) option to do this.