std.debug: miscellaneous fixes

Mostly on macOS, since Loris showed me a not-great stack trace, and I
spent 8 hours trying to make it better. The dyld shared cache is
designed in a way which makes this really hard to do right, and
documentation is non-existent, but this *seems* to work pretty well.
I'll leave the ruling on whether I did a good job to CI and our users.

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/std/debug/cpu_context.zig b/lib/std/debug/cpu_context.zig
index 9859575fa3..b9dd49767f 100644
--- a/lib/std/debug/cpu_context.zig
+++ b/lib/std/debug/cpu_context.zig
@@ -214,6 +214,12 @@ pub fn fromWindowsContext(ctx: *const std.os.windows.CONTEXT) Native {
             .sp = ctx.Sp,
             .pc = ctx.Pc,
         },
+        .thumb => .{ .r = .{
+            ctx.R0,  ctx.R1, ctx.R2,  ctx.R3,
+            ctx.R4,  ctx.R5, ctx.R6,  ctx.R7,
+            ctx.R8,  ctx.R9, ctx.R10, ctx.R11,
+            ctx.R12, ctx.Sp, ctx.Lr,  ctx.Pc,
+        } },
         else => comptime unreachable,
     };
 }