While compiling socat-2.0.0-b5 on cygwin (Windows) I got a few errors and here’s how I fixed it:
xioopts.c: In function 'applyopts_single':
xioopts.c:3998: error: 'struct single' has no member named 'fd1'
xioopts.c:4000: error: 'struct single' has no member named 'fd1'
make[1]: *** [xioopts.o] Error 1
Edit the file xioopts.c in your favorite editor and replace ‘fd1’ by ‘rfd’ in both lines (3998 & 4000). That fixed this error but then I got my next error.

xio-ip.c:480: error: structure has no member named `ipi_spec_dst'
Edit xio-ip.c and comment out the entire snprintf statement in xio-ip.c line 480.

Continue compilation and it should now work fine.

I have used Michal Zalewski’s Ratproxy on Google code. I like it a lot. But I also like to have it on Windows. But it seems that the makefile that comes with ratproxy is not really compatible with cygwin.
If you have the gcc, make, openssl, openssl-dev packages installed on cygwin, all you need to do is remove the -Wno-pointer flag from the CFLAGS entry from the Makefile.
So my Makefile’s CFLAGS line looks like:

CFLAGS  = -Wall -O3 -D_GNU_SOURCE

I also replaced $(CC) with gcc just because I felt like it. 🙂
Compile it with make command.
Do not forget to dos2unix the ratproxy-report.sh otherwise you will get some errors with ‘\r’ and some other random stuff when you run the report generator shell scripts.
Run ratproxy as :
c:\tools\ratproxy>ratproxy.exe -p 8000 -v c:\testdir -w ratlog -d example.com -extifscfjmXCk
Once you have the log to generate a nice looking pretty report:
bash$ ./ratproxy-report.sh ratlog >reportname.html

Update 06/20/2012:
If you get the error shown below:
ratproxy.c: In function `listen_loop':
ratproxy.c:1635:5: error: incompatible type for argument 2 of `waitpid'
/usr/include/sys/wait.h:43:7: note: expected `__wait_status_ptr_t' but argument
is of type `unsigned int *'
Makefile:30: recipe for target `ratproxy' failed
make: *** [ratproxy] Error 1

Do the following:
1. Go to line # 1635 and change the line to while (waitpid(-1,(int*)&x,WNOHANG) > 0);
2. Goto the command line and type

make

You should be able to compile ratproxy.

An interesting thing happened today …I was trying to redirect some input to /dev/null in cygwin…using something like:
some_exec -p params 2>&/dev/null | grep blah
I kept getting an error : bash: Ambiguous redirect.
I then realized that I should probably doing a simple direct and not a re-direct…seemed to solve my problem. Come to think of it…it makes sense, why should I need to redirect when I’m sending it to /dev/null…should simply be able to direct it using:
some_exec -p paraa 2>/dev/null | grep blah