This is incorrect in several ways.  Here's a correct freetype installation (Linux):

```
% pkg-config --cflags freetype2
-I/usr/include/freetype2  
% freetype-config --cflags
-I/usr/include/freetype2
% ls /usr/include/freetype2 
freetype
LS28900-linux% ls /usr/include/freetype2/freetype 
config      ftbbox.h    ftcache.h     fterrdef.h  ftgxval.h   ftlcdfil.h  ftmm.h      ftoutln.h   ftsnames.h  fttrigon.h  t1tables.h  ttunpat.h
freetype.h  ftbdf.h     ftcffdrv.h    fterrors.h  ftgzip.h    ftlist.h    ftmodapi.h  ftpfr.h     ftstroke.h  fttypes.h   ttnameid.h
ftadvanc.h  ftbitmap.h  ftchapters.h  ftgasp.h    ftimage.h   ftlzw.h     ftmoderr.h  ftrender.h  ftsynth.h   ftwinfnt.h  tttables.h
ftautoh.h   ftbzip2.h   ftcid.h       ftglyph.h   ftincrem.h  ftmac.h     ftotval.h   ftsizes.h   ftsystem.h  ftxf86.h    tttags.h
```

i.e. if the user builds with `/usr/include/freetype2` on their include path, they can then `#include <freetype/freetype.h>`.  Current homebrew is missing the intermediate `freetype` directory which moves the headers directly to the top-level (i.e. breaking things).

The symlink suggestion here is a workaround for a broken installation.  It's also non-standard and broken for most users (what is `/opt/local`?)  Far simpler to get it fixed in homebrew properly.  And as a better workaround:

```
    sudo ln -s . /usr/local/include/freetype2/freetype
```

since this will only be created in the Cellar, and hence will be removed on the next upgrade, rather than screw up the user's system long after the bug is fixed. If the symlink remains in `/usr/local/include` directly, after the bug is fixed it will mean that `<freetype>` will actually be `freetype/../freetype2/` i.e. `<freetype/freetype.h>` will not resolve to a valid file since this will become `freetype/../freetype2/freetype/freetype.h`, depending upon the include path ordering.  We shouldn't be making suggestions like this, since non-standard one-off custom hacks cause hard to diagnose long-term problems for our users.

See: https://github.com/Homebrew/homebrew/issues/25256