gpg: Add regular expression support.

* AUTHORS, COPYING.other: Update.
* Makefile.am (SUBDIRS): Add regexp sub directory.
* configure.ac (DISABLE_REGEX): Remove.
* g10/Makefile.am (needed_libs): Add libregexp.a.
* g10/trustdb.c: Remove DISABLE_REGEX support.
* regexp/LICENSE, regexp/jimregexp.c, regexp/jimregexp.h,
  regexp/utf8.c, regexp/utf8.h: New from Jim Tcl.
* regexp/UnicodeData.txt: New from Unicode.
* regexp/Makefile.am, regexp/parse-unidata.awk: New.
* tests/openpgp/Makefile.am: Remove DISABLE_REGEX support.
* tools/Makefile.am: Remove DISABLE_REGEX support.

GnuPG-bug-id: 4843
Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>

regexp/parse-unidata.awk

@@ -0,0 +1,62 @@
+#
+# parse-unidata.awk - generate a table (unicode_case_mapping_upper)
+#
+# Copyright (C) 2020 g10 Code GmbH
+#
+# This file is part of GnuPG.
+#
+# GnuPG is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# GnuPG is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, see <https://www.gnu.org/licenses/>.
+#
+
+# Parse the unicode data from:
+#   https://www.unicode.org/Public/UCD/latest/ucd/UnicodeData.txt
+# to generate case mapping table
+
+BEGIN {
+    print("/* Generated from UnicodeData.txt */")
+    print("")
+    print("static const struct casemap unicode_case_mapping_upper[] = {")
+    FS = ";"
+    count = 0
+}
+
+{
+    code = strtonum(("0x" $1))
+    name = $2
+    class = $3
+    upper = $13
+    lower = $14
+    title = $15
+
+    if (code <= 0x7f) {
+	next
+    }
+    if (code > 0xffff) {
+	next
+    }
+    if ($3 !~ /^L.*/) {
+	next
+    }
+    if (upper != "") {
+	printf("\t{ 0x" tolower($1) ", 0x" tolower(upper) " },")
+	count++
+	if ((count % 4) == 0) {
+	    print("")
+	}
+    }
+}
+
+END {
+    print("\n};")
+}