Dont use closerange() on OS X

The original motivation for this was OpenGL problems caused by the glfw
library on linux because of inherited file descriptors. Dont know if
that applies on OS X.

kitty/child.py

@@ -9,7 +9,7 @@ import fcntl
 import signal
 from threading import Thread
 
-from .constants import terminfo_dir
+from .constants import terminfo_dir, isosx
 
 
 def remove_cloexec(fd):
@@ -52,7 +52,8 @@ class Child:
                 else:
                     os.dup2(slave, i)
             os.close(slave), os.close(master)
-            os.closerange(3, 200)
+            if not isosx:  # Apparently some OS X systemlibraries open file descriptors that cause EXC_GUARD crashes when closed
+                os.closerange(3, 200)
             # Establish the controlling terminal (see man 7 credentials)
             os.close(os.open(os.ttyname(1), os.O_RDWR))
             os.environ['TERM'] = self.opts.term