Not many people will probably care, but I though I might as well share the information I have just in case someone is looking for info. These are the steps I took to fix some small compatibility errors and compile SFmpq on OS X:

1) Download SFmpqapi, SComp, bzip, and zlib
2) Replace #include <malloc.h> with #include <stdlib.h> in windows.cpp/.h, SMem.cpp/.h, and SFmpqapi.cpp/.h
3) Replace #include <windows.h> with #include "windows.h" in SFmpqapi.cpp/.h
4) Compile files in this order:
windows
SErr
SMem
explode
implode (there was a cast from unsigned char* to char* "error" on line 452 for me, easy fixes though)
huffman
crc32
wave
SComp
SFmpqapi
bzip (a simple "make" works to compile it. i needed to compile it or else I would get missing symbol errors, but didn't need to do this for zlib)
5) Compile it all together. I used:
g++ -dynamiclib -o SFmpq.dylib -lz windows.o SFmpqapi.o crc32.o explode.o huffman.o implode.o SComp.o SErr.o SMem.o wave.o bzip2/blocksort.o bzip2/compress.o bzip2/decompress.o bzip2/randtable.o bzip2/bzip2.o bzip2/bzlib.o bzip2/crctable.o bzip2/huffman.o


Thank you to ShadowFlare for making such an awesome dll (or dylib ;P)!

I had fixed some occurrences of malloc.h already, but there was one remaining in the windows.h file, which I changed to stdlib.h just a few minutes ago.

I might give a go at compiling this for linux, as I mostly use linux nowadays and every now and then could do with a working MPQ tool.
I'll let ya'll know how it goes.

Sorry for double post, but you might miss the edit:

In windows.h, you define __declspec twice.

Code

Why is this? It's throwing up an error when I try to compile windows.cpp.

And I also get this error:

Code

I'm not very good at programming, so yeah

At the time, I must not have realized that I didn't need a different one for each of those cases.

As for strdup, try removing it from windows.cpp/.h. Maybe I didn't used to have it including the header that defined it and now it is?

The last time I had tried compiling it in Linux was maybe when I had a computer with Red Hat Linux 7.something installed on another partition.