@WalterBright D_test1() and D_test2() don't test the ABI, they are sanity checks! They run on every OS and every ARCH (32bit and 64bit). Only win64 fails here.

eg. for 6 byte struct sss
test1_out() returns sss(1,2,3), then test1_call_out() checks the struct is the correct value.
test1_inout() returns sss(a+10,b+20,c+30), which test1_call_inout() checks.