If you build refdb from scratch, you will need some libraries installed on your system:
Note: The version numbers in this list do not indicate that it is impossible to build refdb with any lower version number. The numbers just indicate the versions that were used successfully. Lower version numbers may work, higher version numbers are assumed to work in all cases.
libreadline (version 4.1 or later)
libmysqlclient (the version should match the database server version that you use, that is 3.22 or later)
libz (version 1.1.3 or later; not required on systems using glibc)
libexpat (version 1.95.1)
btparse (version 0.33; only required if you want to build the BibTeX import filter)
libnsl, a standard library on Solaris, may be required on this platform.
Note: Some operating systems/distributions use separate packages for the run-time libraries and the development libraries. In order to build refdb from the sources, you need both types of libraries.
If you want to build refdb with Cygwin, you should be aware that not all of the above libraries are available in the standard distribution. The remaining libraries either compile out of the tarball or are available as third-party contributions. Check also the Cygwin mailing list for porting instructions.