FYI: document why Python directories start with ${prefix} unexpanded

[Alexandre Duret-Lutz]

I've installed this on HEAD and branch-1-7.

2003-01-22  Alexandre Duret-Lutz  <address@hidden>

        * automake.texi (Python): Explain that directory variables start
        with either ${prefix} or ${exec_prefix}, and point to the
        `Installation Directory Variables' section of the Autoconf manual.

Index: automake.texi
===================================================================
RCS file: /cvs/automake/automake/automake.texi,v
retrieving revision 1.319
diff -u -r1.319 automake.texi
--- automake.texi       21 Jan 2003 18:02:33 -0000      1.319
+++ automake.texi       22 Jan 2003 21:47:22 -0000
@@ -3913,12 +3913,12 @@
 @code{sys.version[:3]}.
 
 @item PYTHON_PREFIX
-The string @code{$prefix}.  This term may be used in future work
+The string @address@hidden@}}.  This term may be used in future work
 which needs the contents of Python's @code{sys.prefix}, but general
 consensus is to always use the value from configure.
 
 @item PYTHON_EXEC_PREFIX
-The string @code{$exec_prefix}.  This term may be used in future work
+The string @address@hidden@}}.  This term may be used in future work
 which needs the contents of Python's @code{sys.exec_prefix}, but general
 consensus is to always use the value from configure.
 
@@ -3944,6 +3944,15 @@
 This is a convenience variable which is defined as
 @samp{$(pyexecdir)/$(PACKAGE)}.
 @end vtable
+
+All these directory variables have values that start with either
address@hidden@address@hidden or @address@hidden@}} unexpanded.  This works
+fine in @file{Makefiles}, but it makes these variables hard to use in
address@hidden  This is mandated by the GNU conding standard, so
+that the user can run @code{make prefix=/foo install}.  The Autoconf
+manual has a section with more details on this topic
+(@pxref{Installation Directory Variables, , Installation Directory
+Variables, autoconf, The Autoconf Manual}).
 
 
 @node Documentation, Install, Other GNU Tools, Top

-- 
Alexandre Duret-Lutz