libgettextpo: Remove static variable callback_arg.
* gettext-tools/src/read-catalog-abstract.h (po_callback_domain,
po_callback_message, po_callback_comment, po_callback_comment_dot,
po_callback_comment_filepos, po_callback_comment_special,
po_callback_comment_dispatcher): Add a first parameter 'catr'.
* gettext-tools/src/read-catalog-abstract.c (callback_arg): Remove variable.
(parse_start, parse_end): Remove functions.
(catalog_reader_parse): Inline them here.
(po_callback_domain, po_callback_message, po_callback_comment,
po_callback_comment_dot, po_callback_comment_filepos,
po_callback_comment_special, po_parse_comment_filepos,
po_parse_comment_solaris_filepos, po_callback_comment_dispatcher): Add a first
parameter 'catr'.
* gettext-tools/src/po-gram.h: Include read-catalog-abstract.h.
(struct po_parser_state): Add field 'catr'.
* gettext-tools/src/read-po.c (po_parse): Initialize the 'catr' field.
* gettext-tools/src/po-gram-gen.y: Pass ps->catr to po_callback_message,
po_callback_comment_dispatcher, po_callback_domain.
* gettext-tools/src/read-properties.c (properties_parse): Pass catr to
po_callback_comment_dispatcher, po_callback_message.
* gettext-tools/src/read-stringtable.c (special_comment_finish,
comment_line_end, phase4_getc, read_string): Add a first parameter 'catr'.
(stringtable_parse): Pass catr to the functions that need it.
