Often the code comes directly from a Windows computer.
The following steps may be needed to compile it on UNIX:

Modify Makefile to have -DLIN (for 32-bits) or -DLIN64 (for 64-bits)

>> dos2unix Makefile Makefile
>> dos2unix depends.sh depends.sh
>> chmod 755 depends.sh
>> make  // on Solaris, try "gmake"

If compiling as a static library, it is necessary to uncomment
#define _LIB in "src/abc/main/main.c"

To compile with Microsoft Visual Studio higher than 6.0,
remove ABC_CHECK_LEAKS from the preprocessor definitions
for the debug version (Project->Settings->C/C++->Preprocessor Definitions)

If compilation does not start because of the cyclic dependency check, 
try "touching" all files:    find ./ -type f -exec touch "{}" \;

Several things to try if it does not compile on your platform:
- Try running all code (not only Makefile and depends.sh) through dos2unix
- Try the following actions:
  (a) Remove flags from the libs line (LIBS :=) in Makefile
  (b) Remove "src\base\main\libSupport.c" from "src\base\main\module.make"
  (c) Comment calls to Libs_Init() and Libs_End() in "src\base\main\mainInit.c"
- Try linking with gcc (rather than g++)
  For this replace "LD   := g++" with "LD   := gcc -lm" in Makefile
- If your Linux distributin does not have "readline", you may have problems 
  compiling ABC with gcc. Please try installing this library from
  http://tiswww.case.edu/php/chet/readline/rltop.html

To compile the latest version of ABC, you may need to define "LIN" or "LIN64" 
(depending on whether you are using 32- or 64-bit Linux). 
For example, instead of
    OPTFLAGS  := -g -O
use
    OPTFLAGS  := -g -O -DLIN64
in Makefile.

Finally, run regression test:
abc>>> so regtest.script