arch/x86: Make rdrand.c clang friendly

rdrand64() is not clang friendly. Actually it looks like the
function is incorrect on 32bit x86 for all compilers including
gcc, but gcc won't care because the function is never called on

src/arch/x86/rdrand.c:51:15: error: invalid output size for constraint '=a'
             : "=a" (*rand), "=qm" (carry));
1 error generated.

Guard the code correctly if ENV_X86_64 is not set.

Change-Id: Ia565897f5e4caaaccfcb02cf1245b150272dff68
Signed-off-by: Stefan Reinauer <>
Tested-by: build bot (Jenkins) <>
Reviewed-by: Arthur Heymans <>
Reviewed-by: Philippe Mathieu-Daudé <>
1 file changed