wilder-henderson-macbook-pros-imac:include dgh$ ls -l /usr/include/symlink
total 80
lrwxr-xr-x  1 root  wheel  72 Jan 28 14:45 tcl.h -> ../../System/Library/Frameworks/Tcl.framework/Versions/8.5/Headers/tcl.h
lrwxr-xr-x  1 root  wheel  77 Jan 28 14:45 tclDecls.h -> ../../System/Library/Frameworks/Tcl.framework/Versions/8.5/Headers/tclDecls.h
lrwxr-xr-x  1 root  wheel  81 Jan 28 14:45 tclPlatDecls.h -> ../../System/Library/Frameworks/Tcl.framework/Versions/8.5/Headers/tclPlatDecls.h
lrwxr-xr-x  1 root  wheel  79 Jan 28 14:45 tclTomMath.h -> ../../System/Library/Frameworks/Tcl.framework/Versions/8.5/Headers/tclTomMath.h
lrwxr-xr-x  1 root  wheel  84 Jan 28 14:45 tclTomMathDecls.h -> ../../System/Library/Frameworks/Tcl.framework/Versions/8.5/Headers/tclTomMathDecls.h
lrwxr-xr-x  1 root  wheel  70 Jan 28 14:45 tk.h -> ../../System/Library/Frameworks/Tk.framework/Versions/8.5/Headers/tk.h
lrwxr-xr-x  1 root  wheel  75 Jan 28 14:45 tkDecls.h -> ../../System/Library/Frameworks/Tk.framework/Versions/8.5/Headers/tkDecls.h
lrwxr-xr-x  1 root  wheel  82 Jan 28 14:45 tkIntXlibDecls.h -> ../../System/Library/Frameworks/Tk.framework/Versions/8.5/Headers/tkIntXlibDecls.h
lrwxr-xr-x  1 root  wheel  76 Jan 28 14:45 tkMacOSX.h -> ../../System/Library/Frameworks/Tk.framework/Versions/8.5/Headers/tkMacOSX.h
lrwxr-xr-x  1 root  wheel  79 Jan 28 14:45 tkPlatDecls.h -> ../../System/Library/Frameworks/Tk.framework/Versions/8.5/Headers/tkPlatDecls.h