Bump version number for new release

NEWS

@@ -2,6 +2,11 @@ GPP NEWS -- history of user-visible changes
 
 See the end of this file for copying conditions.
 
+
+Version 2.28
+
+    * Fixed typos in documentation (Issues #57 and #61)
+    * Added #sinclude meta-macro for silent includes (Issue #63)
 
 Version 2.27
 
@@ -132,7 +137,7 @@ Version 2.1
 Copyright information:
 
 Copyright (C) 2001 Denis Auroux.
-Copyright (C) 2003, 2004 Tristan Miller.
+Copyright (C) 2003-2023 Tristan Miller.
 
    Permission is granted to anyone to make or distribute verbatim
    copies of this document as received, in any medium, provided that

configure.ac

@@ -2,7 +2,7 @@
 # Process this file with autoconf to produce a configure script.
 
 AC_PREREQ(2.57)
-AC_INIT([GPP], [2.27], [[email protected]], [gpp])
+AC_INIT([GPP], [2.28], [[email protected]], [gpp])
 
 AM_INIT_AUTOMAKE([])
 AC_CONFIG_SRCDIR([src/gpp.c])

doc/gpp.pp

@@ -175,7 +175,7 @@
 $endif$
 $endif$
 %%%%%%%%%%%%%%%%% some headers %%%%%%%%%%%%%%%%%%%
-$define{version}{2.27}$
+$define{version}{2.28}$
 $define{SYNTAX}{
 $pre$
 gpp [$dp$$bra$o$pipe$O$ket$ $I{outfile}$] [$dp$I$I{/include/path}$ ...]
@@ -1483,7 +1483,7 @@ functional abstraction in GPP (in standard mode). Understanding this
 [email protected]$g$.
 $S{COPYRIGHT}$
 Copyright $copy$$nbsp$1996$ndash$2001 Denis Auroux.$BR$
-Copyright $copy$$nbsp$2003$ndash$2020 Tristan Miller.$P$
+Copyright $copy$$nbsp$2003$ndash$2023 Tristan Miller.$P$
 Permission is granted to anyone to make or distribute verbatim copies
 of this document as received, in any medium, provided that the
 copyright notice and this permission notice are preserved, thus giving