DEPENDS_ON_* preprocessor symbols

[Ben Pfaff]

Hi Bruno.  Thank you for fixing the interactions between
__printf__ in gnulib and libintl.

I have a followup question.  While I was trying to figure out
whether PSPP could now drop its definition of DEPENDS_ON_LIBINTL
from its configure.ac, I noticed that there were references to
this preprocessor symbol and two related ones
(DEPENDS_ON_LIBCHARSET and DEPENDS_ON_LIBICONV) in
relocatable.c.  Their purpose was not documented, but I think
that I figured out what they are for.  I'm proposing the
following update to doc/relocatable-maint.texi in gnulib as
explanation.  Is it a correct explanation?  Is it worth
documenting the lib{iconv,intl,charset} functions that the
DEPENDS_ON_* macros call, so that programs can call them
directly?

Thanks,

Ben.

diff --git a/doc/relocatable-maint.texi b/doc/relocatable-maint.texi
index 72c6eaa..1c25901 100644
--- a/doc/relocatable-maint.texi
+++ b/doc/relocatable-maint.texi
@@ -89,6 +89,28 @@ bindtextdomain (PACKAGE, relocate (LOCALEDIR));
 The prototype for this function is in @file{relocatable.h}.
 
 @item
+The @code{set_program_name} function can also configure some
+additional libraries to relocate files that they access, by defining
+corresponding C preprocessor symbols to nonzero values (e.g. with
address@hidden).  The libraries for which this is supported and the
+corresponding preprocessor symbols are:
+
address@hidden @asis
address@hidden libcharset
address@hidden
+
address@hidden libiconv
address@hidden
+
address@hidden libintl
address@hidden
address@hidden table
+
+Defining the symbol for a library makes every program in the package
+depend on that library, whether the program really uses the library or
+not, so this feature should be used with some caution.
+
address@hidden
 If your package installs shell scripts, also import the
 @code{relocatable-script} module.  Then, near the beginning of each
 shell script that your package installs, add the following:

-- 
"Welcome to the Slippery Slope. Here is your handbasket.
 Say, can you work 70 hours this week?"
--Ron Mansolino