Added --with-bashcompletiondir configure option.

By default, bash_completion file named aria2c is installed to the
directory $prefix/share/doc/aria2/bash_completion.  To change the
install directory of the file, use --with-bashcompletiondir option.

README.rst

@@ -206,6 +206,11 @@ using aria2's ``--ca-certificate`` option.  If you don't have CA bundle
 file installed, then the last resort is disable the certificate
 validation using ``--check-certificate=false``.
 
+By default, bash_completion file named ``aria2c`` is installed to the
+directory ``$prefix/share/doc/aria2/bash_completion``.  To change the
+install directory of the file, use ``--with-bashcompletiondir``
+option.
+
 The executable is 'aria2c' in src directory.
 
 aria2 uses CppUnit for automated unit testing. To run the unit test::

configure.ac

@@ -43,6 +43,11 @@ AC_ARG_WITH([ca-bundle],
   AS_HELP_STRING([--with-ca-bundle=FILE],[Use FILE as default CA bundle.]),
   [ca_bundle=$withval], [ca_bundle=""])
 
+AC_ARG_WITH([bashcompletiondir],
+  AS_HELP_STRING([--with-bashcompletiondir=DIR],
+                 [Directory to install bash_completion file]),
+  [bashcompletiondir=$withval], [bashcompletiondir=$docdir/bash_completion])
+
 # Checks for programs.
 AC_PROG_CXX
 AC_PROG_CC
@@ -572,6 +577,8 @@ if test "x$enable_message_digest" = "xyes"; then
 fi
 AM_CONDITIONAL([ENABLE_WEBSOCKET], [test "x$enable_websocket" = "xyes"])
 
+AC_SUBST([bashcompletiondir])
+
 AC_CONFIG_FILES([Makefile
 		src/Makefile
 		test/Makefile
@@ -611,3 +618,4 @@ echo "Metalink:       $enable_metalink"
 echo "XML-RPC:        $enable_xml_rpc"
 echo "Message Digest: $enable_message_digest"
 echo "WebSocket:      $enable_websocket"
+echo "bash_completion dir: $bashcompletiondir"

doc/Makefile.am

@@ -4,6 +4,9 @@ doc_xmlrpcdir = $(docdir)/xmlrpc
 dist_doc_xmlrpc_DATA = xmlrpc/aria2mon \
 	xmlrpc/aria2rpc \
 	xmlrpc/README.txt
+
 doc_bashcompletiondir = $(docdir)/bash_completion
-dist_doc_bashcompletion_DATA = bash_completion/README.txt \
-	bash_completion/aria2c
+dist_doc_bashcompletion_DATA = bash_completion/README.txt
+
+doc_bashcompletionscriptdir = @bashcompletiondir@
+dist_doc_bashcompletionscript_DATA = bash_completion/aria2c