I dont have any time to explore compiler flags, now.
I just copy here my compiled old version (3.9.1, but adaptated for 3.9.4 pas unit)

I hope that soon will deal with this.

PS: Some explanations for this version.
This code work as Windows as MacOsX.
There is two libtiff.a in pack.
libtiff.a - for mac os
libtiff-win.a - for windows (for compile - rename it to libtiff.a)

PPS: For compiling I use this link :
  http://www.kyngchaos.com/macosx/build/libtiff
  (some compiler flags are here)

Galfar, registration was successful =)

About tifflib under Mac - I forget compilation keys, but I have already compiled tifflib 3.9.1 under mac.
I will upload it... soon...

But with tifflib 3.9.4 under macos I have a problem..
I was build obj files for i386 architechture, but for success compilation need {$Linklib libtiff} and libtiff.a - x86-64 architechture somehow (i view it by otool)

Therefore I need correct compilation keys.
Now I compile tifflib as:

./configure CFLAGS="-arch i386"
make

But it not enough...

PS: sorry my english, but i think you understand me))