WUSBL185083-S4C:~ bl185083$ brew install trash
==> Downloading https://github.com/ali-rantakari/trash/archive/v0.8.5.tar.gz
Already downloaded: /Library/Caches/Homebrew/trash-0.8.5.tar.gz
==> make
Last 15 lines from /Users/BL185083/Library/Logs/Homebrew/trash/01.make:
./HGUtils.h:29:9: fatal error: 'Cocoa/Cocoa.h' file not found
#import <Cocoa/Cocoa.h>
        ^
1 error generated.
In file included from HGCLIUtils.m:30:
./HGCLIUtils.h:30:9: fatal error: 'Cocoa/Cocoa.h' file not found
#import <Cocoa/Cocoa.h>
        ^
1 error generated.
In file included from fileSize.m:32:
./fileSize.h:32:10: fatal error: 'AppKit/AppKit.h' file not found
#include <AppKit/AppKit.h>
         ^
1 error generated.
make: *** [trash] Error 1

READ THIS: https://git.io/brew-troubleshooting