native powerpc64-gcc and clang 3.7.1 on powerpc64: __BIGGEST_ALIGNMENT__ mismatch and a few more

[Mark Millard]

Intersting powerpc64-gcc's g++ (5.2) vs. clang++ (3.7.1) (all native on powerpc64) macro differences for default conditions:

> # more just_main.cpp 
> int main(void)
> { return 0; }

> $ pkg which /usr/local/bin/powerpc64-portbld-freebsd11.0-g++
> /usr/local/bin/powerpc64-portbld-freebsd11.0-g++ was installed by package powerpc64-gcc-5.2.0_1

> # /usr/local/bin/powerpc64-portbld-freebsd11.0-g++ -std=c++11 -dM -E just_main.cpp | sort > ~/powerpc64_gcc_52_macros.txt

> # clang++ -std=c++11 -dM -E just_main.cpp  | sort > ~/clang++371_macros.txt

> # diff -U 100 ~/powerpc64_gcc_52_macros.txt ~/clang++371_macros.txt
> --- /root/powerpc64_gcc_52_macros.txt   2016-01-24 17:51:51.333696000 -0800
> +++ /root/clang++371_macros.txt 2016-01-24 17:49:34.592012000 -0800
. . .
> -#define __BIGGEST_ALIGNMENT__ 16
> +#define __BIGGEST_ALIGNMENT__ 8
. . .
> -#define __CHAR16_TYPE__ short unsigned int
> +#define __CHAR16_TYPE__ unsigned short
. . .
> -#define __CMODEL_MEDIUM__ 1
. . .
> -#define __GNUC__ 5
> -#define __GNUG__ 5
> -#define __GXX_ABI_VERSION 1009
. . .
> +#define __GNUC__ 4
> +#define __GNUG__ 4
> +#define __GXX_ABI_VERSION 1002
. . .
> +#define __NATURAL_ALIGNMENT__ 1
. . .
> -#define __cpp_binary_literals 201304
. . .
> -#define __cpp_runtime_arrays 198712
> -#define __cpp_rvalue_reference 200610
> +#define __cpp_rvalue_references 200610
. . .

===
Mark Millard
markmi at dsl-only.net