PR linker/4844

PR linker/4844
* genscript.sh: Add support for generating a .xa script for use with the --auto-import option.
* ld.texinfo: Document the new behaviour of the --auto-import option.
* ldint.texinfo: Document new script generation.
* emulparams/i386pe.sh (GENERATE_AUTO_IMPORT): Define.
* emulparams/i386pe_posix.sh (GENERATE_AUTO_IMPORT): Define.
* emulparams/i386pep.sh (GENERATE_AUTO_IMPORT): Define.
* emultemp/pe.em (..._get_script): Support the use of the auto import script.
* scripttempl/pe.sc: Put the .rdata input sections into the .data output section when creating an auto import script.
* scripttempl/pep.sc: Likewise.