* install.texi (sco3.2v5): Document new --with-gnu-as flag.
* config/i386/sco5.h (JUMP_TABLES_IN_TEXT_SECTION): Defined as
  in other targets.
  (USE_GAS): Conditionalize away native assembler usage.
* config/i386/sco5gas.h: New file.
* config/i386/t-sco5gas: New file.
* configure.in (ix86-sco3.2v5*): Use new files if --with-gnu-as

From-SVN: r20890