add portable *SAN bot

This would have caught my bug:

    ==11454==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7ffd28d75191
    at pc 0x0000005365f2 bp 0x7ffd28d6eb70 sp 0x7ffd28d6eb68
    WRITE of size 4 at 0x7ffd28d75191 thread T0
        #0 0x5365f1  (/home/mtklein/skcms/out/clang.xsan-portable/tests+0x5365f1)
        #1 0x524b5d  (/home/mtklein/skcms/out/clang.xsan-portable/tests+0x524b5d)
        #2 0x51e3fd  (/home/mtklein/skcms/out/clang.xsan-portable/tests+0x51e3fd)
        #3 0x53c886  (/home/mtklein/skcms/out/clang.xsan-portable/tests+0x53c886)
        #4 0x7f8d92d16b16  (/lib/x86_64-linux-gnu/
        #5 0x41d3d9  (/home/mtklein/skcms/out/clang.xsan-portable/tests+0x41d3d9)

    Address 0x7ffd28d75191 is located in stack of thread T0 at offset 22641 in frame
        #0 0x53947f  (/home/mtklein/skcms/out/clang.xsan-portable/tests+0x53947f)

I need to dig a little deeper into unsigned integer overflow
in half<->float math before we can turn on -fsanitize=integer.

Change-Id: Id85fd3f2616df02556d8f04141476a3efe74d158
Auto-Submit: Mike Klein <>
Reviewed-by: Mike Klein <>
Commit-Queue: Mike Klein <>
2 files changed