Add globbing pattern support to #include and #include_once

* doc/grecs-syntax.texi: Document changes to the #include statement.
* doc/grecs_config.5: Likewise.
* src/preproc.c (include_glob, include_pos)
(include_once): New statics.
(pp_list_find): Return 0 if list is NULL.
(incl_copy): New statics.
(source_lookup): Use incl_copy as the copy function.
(pop_source): If more glob expansions are available, push next one
onto input stack.
(isglob): New static.
(parse_include): Support globbing patterns.
* tests/Makefile.am: Add new testes.
* tests/testsuite.at: Likewise.
* tests/incl00.at: New test case.
* tests/incl01.at: New test case.
* tests/incl02.at: New test case.
* tests/incl03.at: New test case.

2 files changed, 37 insertions, 15 deletions

diff --git a/doc/grecs-syntax.texi b/doc/grecs-syntax.texi
index c10cab6..da59d03 100644
--- a/doc/grecs-syntax.texi
+++ b/doc/grecs-syntax.texi
@@ -1,5 +1,5 @@
 @c This file is part of grecs - Gray's Extensible Configuration System
-@c Copyright (C) 2007, 2009-2012 Sergey Poznyakoff
+@c Copyright (C) 2007, 2009-2014 Sergey Poznyakoff
 @c
 @c Grecs is free software; you can redistribute it and/or modify
 @c it under the terms of the GNU General Public License as published by
@@ -82,12 +82,23 @@ next physical newline character.
 @kwindex #include
 @item #include <@var{file}>
 @itemx #include @var{file}
-Include the contents of the file @var{file}.  If @var{file} is an
-absolute file name, both forms are equivalent.  Otherwise, the form
-with angle brackets searches for the file in the @dfn{include 
-search path}, while the second one looks for it in the current working
-directory first, and, if not found there, in the include search
-path.
+Include the contents of the file @var{file}.  There are three possible
+use cases.
+
+If @var{file} is an absolute file name, the named file is included.
+An error message will be issued if it does not exist.
+
+If @var{file} contains wildcard characters (@samp{*}, @samp{[},
+@samp{]} or @samp{?}), it is interpreted as shell globbing pattern and
+all files matching that pattern are included, in lexicographical
+order.  If no files match the pattern, the statement is silently
+ignored.
+
+Otherwise, the form with angle brackets searches for file in the
+@dfn{include  search path}, while the second one looks for it in the
+current working directory first, and, if not found there, in the
+include search path.  If the file is not found, an error message will
+be issued.
 
 The default include search path is:
 
diff --git a/doc/grecs_config.5 b/doc/grecs_config.5
index 80f7bcc..82633d5 100644
--- a/doc/grecs_config.5
+++ b/doc/grecs_config.5
@@ -1,5 +1,5 @@
 .\" This file is part of grecs -*- nroff -*-
-.\" Copyright (C) 2007, 2009-2012 Sergey Poznyakoff
+.\" Copyright (C) 2007, 2009-2014 Sergey Poznyakoff
 .\"
 .\" Grecs is free software; you can redistribute it and/or modify
 .\" it under the terms of the GNU General Public License as published by
@@ -14,7 +14,7 @@
 .\" You should have received a copy of the GNU General Public License
 .\" along with Grecs.  If not, see <http://www.gnu.org/licenses/>.
 .\"
-.TH GRECS_CONFIG 3 "May 4, 2011" "GRECS" "Grecs User Reference"
+.TH GRECS_CONFIG 3 "December 25, 2014" "GRECS" "Grecs User Reference"
 .SH NAME
 \fBGrecs\fR configuration file syntax 
 .SH DESCRIPTION
@@ -64,12 +64,23 @@ sign and end with the next physical newline character.
 .TP
 .BR "#include " "file"
 .PD
-Include the contents of the file \fIfile\fR.  If it is an
-absolute file name, both forms are equivalent.  Otherwise, the form
-with angle brackets searches for the file in the \fIinclude 
-search path\fR, while the second one looks for it in the current working
-directory first, and, if not found there, in the include search
-path.
+Include the contents of the file \fIfile\fR.  There are three possible
+use cases.
+
+If \fIfile\fR is an absolute file name, the named file is included.
+An error message will be issued if it does not exist.
+
+If \fIfile\fR contains wildcard characters (\fB*\fR, \fB[\fR,
+\fB]\fR or \fB?\fR), it is interpreted as shell globbing pattern and
+all files matching that pattern are included, in lexicographical
+order.  If no files match the pattern, the statement is silently
+ignored.
+
+Otherwise, the form with angle brackets searches for file in the
+\fIinclude  search path\fR, while the second one looks for it in the
+current working directory first, and, if not found there, in the
+include search path.  If the file is not found, an error message will
+be issued.
 .sp
 The default include search path is:
 .sp