import elementary functions as intrinsics

Importing them as intrinsics enables GCC to treat them as builtins
whose behavior is known by GCC.

Specifically, if they aren't intrinsics, calls to Sin and Cos won't be
combined into sincos.

We still need to make Sin and Cos wrappers inline in user-exposed
interfaces to get users the benefit of this transformation.
That is forthcoming in a separate patch.


for  gcc/ada/ChangeLog

	* libgnat/a-numaux.ads: Make all imports Intrinsic.
	* libgnat/a-numaux__darwin.ads: Likewise.
	* libgnat/a-numaux__libc-x86.ads: Likewise.
	* libgnat/a-numaux__vxworks.ads: Likewise.