Fix build on darwin: stat structure

[kirelagin]

This change is 

[nh2]

I get:

% stack test
hatrace-0.1.0.0: build (lib + exe + test)
Preprocessing library for hatrace-0.1.0.0..
/home/niklas/src/haskell/hatrace/Types.hsc:106:7: error: #elif with no expression
/home/niklas/src/haskell/hatrace/Types.hsc:127:7: error: #elif with no expression
Types.hsc: In function ‘main’:
/home/niklas/src/haskell/hatrace/Types.hsc:106:7: error: #elif with no expression
/home/niklas/src/haskell/hatrace/Types.hsc:127:7: error: #elif with no expression
/home/niklas/src/haskell/hatrace/Types.hsc:131:7: error: #elif with no expression
/home/niklas/src/haskell/hatrace/Types.hsc:152:7: error: #elif with no expression
compiling .stack-work/dist/x86_64-linux/Cabal-2.4.0.1/build/System/Hatrace/Types_hsc_make.c failed (exit code 1)

Should this be #else?

[kirelagin]

Huh, weird that it worked. I force-pushed a change.