sw_vers does not use Gestalt

on 

$ nm /usr/bin/sw_vers
[..]
         U __CFCopyServerVersionDictionary
         U __CFCopySystemVersionDictionary
[..]

$ DYLD_IMAGE_SUFFIX=_debug gdb /usr/bin/sw_vers
[..]

Breakpoint 10, CFURLCreateWithFileSystemPath (allocator=0x0, 
filePath=0x2ee828, 
fsType=kCFURLPOSIXPathStyle, 
isDirectory=0 '\000') 
at URL.subproj/CFURL.c:3480

(gdb) bt
#0  CFURLCreateWithFileSystemPath (allocator=0x0, 
      filePath=0x2ee828, 
      fsType=kCFURLPOSIXPathStyle, 
      isDirectory=0 '\000') 
      at URL.subproj/CFURL.c:3480
#1  0x00262866 in _CFCopyVersionDictionary (path=0x2ee828) 
      at Base.subproj/CFUtilities.c:253
#2  0x0026282a in _CFCopySystemVersionDictionary () 
      at Base.subproj/CFUtilities.c:309
#3  0x000019ae in ?? ()
#4  0x00001896 in ?? ()
#5  0x000017bd in ?? ()

(gdb) call CFShow(0x2ee828)
/System/Library/CoreServices/SystemVersion.plist