- token.def: enable T_DOT_IDENT
- tunit.h: add S_DOT_IDENT and make it share attributes with S_DOT_FILE,
describe available section types, add tunit_strtab_section_enter(),
rearrange declarations
- tunit.c: implement tunit_strtab_section_enter()
- parse.c: generalize .file parser, use it also for .ident
- input.c: handle S_DOT_IDENT, lookup or create .comment strtab section,
append given string literal to that section
- add optional ->output() method to struct section
- make output_section() use ->output() if present
- make strtab_init() set up ->output
- change strtab_write() into a trivial wrapper for output_section()
- embed a strtab's associated section in the strtab itself
- change append_section() to enter name before reading dot
- synthesize .shstrtab with append_section(), remove old kludge
remove ->image == NULL test in append_section, output_shdr
don't store dummy value in section_strtab.image or section_shstrtab.image
hoist symtab declaration to output() top-level, don't store it in
section_symtab.image
drop fixmes at assignments to .dot as they are Ok
