va_list definition in va-alpha.h

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Version: 2.95.1
System: alpha-dec-osf4.0*

va_list is multiply defined in headers that are generated by gcc:
va_list.h and va-alpha.h.  This causes errors on every compiler input
that includes <va_list.h>.  va_list.h sets and checks _VA_LIST
preprocessor flags on defining va_list typedef.  va-alpha.h only sets
it, but does not check.

My fix: add `#ifndef _VA_LIST ... #endif' to va_list definition in
gcc/gcc/ginclude/va-alpha.h.