Trying to build FreeRadius from Cygwin I always have the same compilation error: gcc .libs/radiusd.def .libs/radiusdS.o -o radiusd.exe .libs/acct.o .libs/auth.o .libs/client.o .libs/conffile.o .libs/crypt.o .libs/exec.o .libs/files.o .libs/listen.o .libs/log.o .libs/mainconfig.o .libs/modules.o .libs/modcall.o .libs/radiusd.o .libs/stats.o .libs/session.o .libs/threads.o .libs/util.o .libs/valuepair.o .libs/version.o .libs/xlat.o .libs/event.o .libs/realms.o .libs/evaluate.o .libs/vmps.o .libs/detail.o -Wl,--export-dynamic /freeradius-server-2.1.8/src/lib/.libs/libfreeradius-radius.a -lws2_32 -lresolv -lpthread -lcrypt /usr/lib/libltdl.dll.a -lssl -lcrypto /usr/lib/gcc/i686-pc-cygwin/4.3.4/../../../../i686-pc-cygwin/bin/ld: warning: --export-dynamic is not supported for PE targets, did you mean --export-all-symbols? .libs/modules.o: In function `setup_modules': /freeradius-server-2.1.8/src/main/modules.c:1358: undefined reference to `_lt_libltdl_LTX_preloaded_symbols' collect2: ld returned 1 exit status rm -f .libs/radiusdS.o make[4]: *** [radiusd] Error 1 make[4]: Leaving directory `/freeradius-server-2.1.8/src/main' make[3]: *** [common] Error 2 make[3]: Leaving directory `/freeradius-server-2.1.8/src' make[2]: *** [all] Error 2 make[2]: Leaving directory `/freeradius-server-2.1.8/src' make[1]: *** [common] Error 2 make[1]: Leaving directory `/freeradius-server-2.1.8' make: *** [all] Error 2 I think that there are some problems with libtool and libltl, then searching in the mail list I made the changes said by Alan Dekok, in the src file 'freeradius-server-2.1.8\src\main\modules.c', Adding: #define lt__PROGRAM__LTX_preloaded_symbols \ lt_libltdl_LTX_preloaded_symbols And in the Make.inc: Update CFLAGS to add -DIE_LIBTOOL_DIE But always obtain the same compilation error. I need to use a FreeRadius version which supports Sha256 as the certificate signature Any help would be fantastic. I need to use FreeRadius under Cygwin and there isn´t a lot of information in the mailing list. Thanks, Jose Manuel