[PATCH 2/3] sys/cdefs.h: export __attribute_alloc_size__

[Roland McGrath]

__VA_ARGS__ is C99 and so gets warnings under -std=c89 -pedantic.
We should avoid it rather than relying on the system-header exception.
Here it's trivial just to do:

	# define __attribute_alloc_size__(params) \
	     __attribute__ ((__alloc_size__ params))

	extern void *blah (size_t, size_t) __attribute_alloc_size__ ((1, 2));

> 	* include/sys/cdefs.h (__attribute_alloc_size): Delete.

Say, "Macro removed."

> 	* misc/sys/cdefs.h (__attribute_alloc_size__): Define.

Say, "New macro."

> +/* Tell gcc where to find the size param for malloc funcs.  */

Use full English words, correct capitalization for things like proper nouns
(i.e. "GCC"), and a fully coherent explanation.  Here I'd write:

/* Tell the compiler which arguments to an allocation function
   indicate the size of the allocation.  */

> +# define __attribute_alloc_size__(...) \
> +     __attribute__ ((__alloc_size__ (__VA_ARGS__)))

The norm here is to indent the continuation line just two spaces.
A reasonable alternative is two spaces from "define".  Three spaces
from "define" is not compatible with our style.

> +# define __attribute_alloc_size__(...) /* Ignore */

It's preferable to use a tab (or multiple tabs, if there is something
nearby to line up with) between the lhs and rhs of a macro definition.
The comment is not really necessary at all here, but if it's there
it should read "/* Ignore.  */".  

The contrary style examples in the file are errors to be fixed,
not models to be followed.

The change is OK with those issues fixed.


Thanks,
Roland