[doc] Improve Perl requirements documentation (PR bootstrap/48135)

[Rainer Orth <ro at CeBiTec dot Uni-Bielefeld dot DE>]

While reviewing PR bootstrap/48135, it came up that the Perl
requirements in install.texi are inaccurate:

* On some platforms (Darwin, Solaris), Perl is a build-time requirement,
  but documented with the development requirements only.

* On Solaris with symbol versioning enabled, it is always necessary
  since libgomp is versioned and built even in a C-only bootstrap.

The following patch reflects this.  Tested during a i386-pc-solaris2.11
bootstrap.

Ok for mainline and 4.6 branch?

Btw., any word on

	[doc] Update install.texi for Solaris 2, IRIX, Tru64 UNIX
        http://gcc.gnu.org/ml/gcc-patches/2011-03/msg01013.html

While I don't need approval for mainline, it would be helpful to get
this into 4.6, too.

Thanks.

	Rainer


2011-03-19  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	PR bootstrap/48135
	* doc/install.texi (Prerequisites): Move Perl to build
	requirements.  Always necessary on Solaris 2 with Sun ld.

diff -r f40ef4501161 gcc/doc/install.texi
--- a/gcc/doc/install.texi	Sat Mar 19 09:09:43 2011 +0100
+++ b/gcc/doc/install.texi	Sat Mar 19 10:25:51 2011 +0100
@@ -303,6 +303,22 @@
 systems' @command{tar} programs will also work, only try GNU
 @command{tar} if you have problems.
 
+@item Perl version 5.6.1 (or later)
+
+Necessary when targetting Darwin, building @samp{libstdc++},
+and not using @option{--disable-symvers}.
+Necessary when targetting Solaris 2 with Sun @command{ld} and not using
+@option{--disable-symvers}.  A helper
+script needs @samp{Glob.pm}, which is missing from @command{perl} 5.005
+included in Solaris@tie{}8.  The bundled @command{perl} in Solaris@tie{}9 and up
+works.
+
+Necessary when regenerating @file{Makefile} dependencies in libiberty.
+Necessary when regenerating @file{libiberty/functions.texi}.
+Necessary when generating manpages from Texinfo manuals.
+Used by various scripts to generate some files included in SVN (mainly
+Unicode-related and rarely changing) from source tables.
+
 @item GNU Multiple Precision Library (GMP) version 4.3.2 (or later)
 
 Necessary to build GCC@.  If you do not have it installed in your
@@ -447,21 +463,6 @@
 Necessary to access the SVN repository.  Public releases and weekly
 snapshots of the development sources are also available via FTP@.
 
-@item Perl version 5.6.1 (or later)
-
-Necessary when regenerating @file{Makefile} dependencies in libiberty.
-Necessary when regenerating @file{libiberty/functions.texi}.
-Necessary when generating manpages from Texinfo manuals.
-Necessary when targetting Darwin, building @samp{libstdc++},
-and not using @option{--disable-symvers}.
-Necessary when targetting Solaris 2 with Sun @command{ld}, building
-@samp{libstdc++}, and not using @option{--disable-symvers}.  A helper
-scripts needs @samp{Glob.pm}, which is missing from @command{perl} 5.005
-included in Solaris@tie{}8.  The bundled @command{perl} in Solaris@tie{}9 and up
-works.
-Used by various scripts to generate some files included in SVN (mainly
-Unicode-related and rarely changing) from source tables.
-
 @item GNU diffutils version 2.7 (or later)
 
 Useful when submitting patches for the GCC source code.


-- 
-----------------------------------------------------------------------------
Rainer Orth, Center for Biotechnology, Bielefeld University