completely ignored by @command{aclocal}, use @samp{##} as the comment
leader.
-When @command{aclocal} detects that the file containing the macro
-definition is in a subdirectory of your package, it will use
-@code{m4_include} instead of copying it; this makes the package
-smaller and eases dependency tracking. This only works if the
-subdirectory containing the macro was specified as a relative search
-path with @command{aclocal}'s @code{-I} argument. (@pxref{Local
-Macros} for an example.) Any macro which is found in a system-wide
-directory, or via an absolute search path will be copied.
-
-The contents of @file{acinclude.m4}, if it exists, are also
+When a file selected by @command{aclocal} is located in a subdirectory
+specified as a relative search path with @command{aclocal}'s @code{-I}
+argument, @command{aclocal} assumes the file belongs to the package
+and uses @code{m4_include} instead of copying it into
+@file{aclocal.m4}. This makes the package smaller, eases dependency
+tracking, and cause the file to be distributed automatically.
+(@pxref{Local Macros} for an example.) Any macro which is found in a
+system-wide directory, or via an absolute search path will be copied.
+So use @code{-I `pwd`/reldir} instead of @code{-I reldir} whenever
+some relative directory need to be considered outside the package.
+
+The contents of @file{acinclude.m4}, if this file exists, are also
automatically included in @file{aclocal.m4}. We recommend against
using @file{acinclude.m4} in new packages (@pxref{Local Macros}).