This isn't just removing support for gcc 2 it is removing support for
anything that doesn't define __GNUC__ and implement all the gnu
attributes which isn't what we want.
On Thu, Oct 01, 2015 at 07:34:48PM -0400, Michael McConville wrote:
> Index: sys/cdefs.h
> ===================================================================
> RCS file: /cvs/src/sys/sys/cdefs.h,v
> retrieving revision 1.39
> diff -u -p -r1.39 cdefs.h
> --- sys/cdefs.h 18 Apr 2014 11:51:17 -0000 1.39
> +++ sys/cdefs.h 1 Oct 2015 23:31:42 -0000
> @@ -88,30 +88,17 @@
> #endif /* !(__STDC__ || __cplusplus) */
>
> /*
> - * GCC1 and some versions of GCC2 declare dead (non-returning) and
> - * pure (no side effects) functions using "volatile" and "const";
> - * unfortunately, these then cause warnings under "-ansi -pedantic".
> - * GCC >= 2.5 uses the __attribute__((attrs)) style. All of these
> - * work for GNU C++ (modulo a slight glitch in the C++ grammar in
> - * the distribution version of 2.5.5).
> + * GCC >= 2.5 and GNU C++ use the __attribute__((attrs)) style to
> + * declare dead (non-returning) and pure (no side effects)
> + * functions.
> */
>
> -#if !__GNUC_PREREQ__(2, 5) && !defined(__PCC__)
> -#define __attribute__(x) /* delete __attribute__ if non-gcc or
> gcc1 */
> -#if defined(__GNUC__) && !defined(__STRICT_ANSI__)
> -#define __dead __volatile
> -#define __pure __const
> -#endif
> -#elif !defined(__STRICT_ANSI__)
> +#if !defined(__STRICT_ANSI__)
> #define __dead __attribute__((__noreturn__))
> #define __pure __attribute__((__const__))
> #endif
>
> -#if __GNUC_PREREQ__(2, 7)
> #define __unused __attribute__((__unused__))
> -#else
> -#define __unused /* delete */
> -#endif
>
> #if __GNUC_PREREQ__(3, 1)
> #define __used __attribute__((__used__))
> @@ -161,10 +148,10 @@
> #endif
>
> /*
> - * GNU C version 2.96 adds explicit branch prediction so that
> - * the CPU back-end can hint the processor and also so that
> - * code blocks can be reordered such that the predicted path
> - * sees a more linear flow, thus improving cache behavior, etc.
> + * GNU offers explicit branch prediction so that the CPU back-end
> + * can hint the processor and also so that code blocks can be
> + * reordered such that the predicted path sees a more linear flow,
> + * thus improving cache behavior, etc.
> *
> * The following two macros provide us with a way to utilize this
> * compiler feature. Use __predict_true() if you expect the expression
> @@ -188,13 +175,8 @@
> * basic block reordering that this affects can often generate
> * larger code.
> */
> -#if __GNUC_PREREQ__(2, 96)
> #define __predict_true(exp) __builtin_expect(((exp) != 0), 1)
> #define __predict_false(exp) __builtin_expect(((exp) != 0), 0)
> -#else
> -#define __predict_true(exp) ((exp) != 0)
> -#define __predict_false(exp) ((exp) != 0)
> -#endif
>
> /* Delete pseudo-keywords wherever they are not available or needed. */
> #ifndef __dead
> @@ -214,26 +196,12 @@
> * alignment of messages exchanged with hardware or other systems.
> */
>
> -#if __GNUC_PREREQ__(2, 7) || defined(__PCC__)
> #define __packed __attribute__((__packed__))
> #define __aligned(x) __attribute__((__aligned__(x)))
> -#endif
>
> -#if !__GNUC_PREREQ__(2, 8)
> -#define __extension__
> -#endif
> -
> -#if __GNUC_PREREQ__(2, 8) || defined(__PCC__)
> #define __statement(x) __extension__(x)
> -#else
> -#define __statement(x) (x)
> -#endif
>
> -#if __GNUC_PREREQ__(3, 0)
> #define __malloc __attribute__((__malloc__))
> -#else
> -#define __malloc
> -#endif
>
> #if defined(__cplusplus)
> #define __BEGIN_EXTERN_C extern "C" {
>
