[PATCH] PR libstdc++/79789 fix non-reserved names in headers

[David Edelsohn]

This patch caused a new regression on AIX.

- David

FAIL: 17_intro/names.cc (test for excess errors)
Excess errors:
/tmp/GCC/gcc/include-fixed/sys/types.h:600: error: expected
unqualified-id before '[' token
/tmp/GCC/gcc/include-fixed/sys/types.h:600: error: expected ')' before '[' token
/tmp/GCC/gcc/include-fixed/sys/types.h:668: error: expected
unqualified-id before '[' token
/tmp/GCC/gcc/include-fixed/sys/types.h:668: error: expected ')' before '[' token
/tmp/GCC/gcc/include-fixed/stdlib.h:332: error: 'parameter' declared
as function returning a function
/tmp/GCC/gcc/include-fixed/stdlib.h:332: error: expected
primary-expression before 'void'
/tmp/GCC/gcc/include-fixed/math.h:1458: error: expected unqualified-id
before ',' token
/tmp/GCC/gcc/include-fixed/math.h:1458: error: expected ')' before ',' token

AIX types.h:600 is

typedef struct { int r[1]; } *  physadr_t;

stdlib.h:332 is

        extern int      at_quick_exit(void (*f)(void));

math.h:1458 is

     struct dbl_hypot {
         double x, y;
     };