* pa.h (architecture_type): New enum.
        (pa_arch_string, pa_arch): Declare.
        (MASK_PA_10, MASK_PA_20): New flags.
        (TARGET_SWITCHES): Add pa-risc-2-0.  Update docs for PA1.0 codegen.
        (TARGET_OPTIONS): Add -march= option.
        * pa.c (pa_arch, pa_arch_string):  Define.
        (override_options):  Set them.
        * pa/pa-hpux10.h (ASM_FILE_START):  Output LEVEL 2.0 asm directive for
        2.0 architecture.
        * invoke.texi (Option Summary, HPPA Options):  Document new
        architecture flags.

From-SVN: r26637