charconv: Add autogen.sh script

AM_ICONV macro depends on gettext installation. Unfortunately autoreconf is
not able to install config.rpath file so do it manually in autogen.sh.

See reported bug:
https://lists.gnu.org/archive/html/bug-gettext/2011-10/msg00012.html

.gitignore

@@ -18,6 +18,7 @@ aclocal.m4
 autom4te.cache
 config.guess
 config.log
+config.rpath
 config.status
 config.sub
 configure

README

@@ -49,5 +49,5 @@ repository, you will find that you can not run "./configure" straight away
 because it, like other autogenerated files for the build system, is not included
 in the repository.
 
-First, autoconf and automake have to be installed.  Then you can run
-"autoreconf -i" to generate all the required files.
+First, autoconf, automake and gettext have to be installed.  Then you can run
+"./autogen.sh" to generate all the required files.

README.md

@@ -52,5 +52,5 @@ repository, you will find that you can not run `./configure` straight away
 because it, like other autogenerated files for the build system, is not included
 in the repository.
 
-First, autoconf and automake have to be installed.  Then you can run `autoreconf
--i` to generate all the required files.
+First, autoconf, automake and gettext have to be installed.  Then you can run
+`./autogen.sh` to generate all the required files.

autogen.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+# Install config.rpath which is needed for AM_ICONV macro
+for dir in "$GETTEXT_DIR" /usr/share/gettext /usr/local/share/gettext; do
+  if test -f "$dir/config.rpath"; then
+    test -f config.rpath || echo "autogen.sh: installing './config.rpath'"
+    cp -f "$dir/config.rpath" .
+    break
+  fi
+done
+
+aclocal --force
+autoconf --force
+automake --add-missing --copy --force-missing