libcURL unresolved externals after 7.36 rebuild

Question

Ok, doing an old VC project did not work, so I tried based on the documentation discussing the winbuild folder and directly running the nmake /f Makefile.vc... and STILL get unresolved externals. This SHOULD NOT be this difficult on such a widely used and maintained system. All from a brand-new fresh download as of today.

I am using VS2013 command line prompt and from capturing the output via > redirection to text file and 2> redirecting error content I get

nmake /f Makefile.vc mode=dll VS=12 > compileResult.txt 2> compileError.txt

(Error content)

Microsoft (R) Program Maintenance Utility Version 12.00.21005.1
Copyright (C) Microsoft Corporation.  All rights reserved.

NMAKE : fatal error U1077: '"C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\BIN\link.exe"' : return code '0x460'
Stop.
NMAKE : fatal error U1077: '"C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\BIN\nmake.exe"' : return code '0x2'
Stop.

(Rest of the build content)

configuration name: libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl
Using SSL:
Using SSH2:
Using ZLIB:
Using IDN: true
Using IPv6: true
Using SSPI: true
Using SPNEGO: true
Using WinSSL: true
CFLAGS: /I. /I ../lib /I../include /nologo /W3 /EHsc /DWIN32 /FD /c /DBUILDING_LIBCURL /I"../../deps/include" /DUSE_WIN32_IDN /DWANT_IDN_PROTOTYPES /DUSE_IPV6 /DUSE_WINDOWS_SSPI /DUSE_SCHANNEL /DHAVE_SPNEGO
LFLAGS: /nologo /machine:x86 "/LIBPATH:../../deps/lib"
GenPDB:
Debug:
Machine: x86
    link.exe /DLL ws2_32.lib wldap32.lib advapi32.lib Normaliz.lib /out:..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib\libcurl.dll  /IMPLIB:..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib\libcurl.lib /nologo /machine:x86 "/LIBPATH:../../deps/lib" ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/file.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/timeval.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/base64.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/hostip.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/progress.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/formdata.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/cookie.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/http.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/sendf.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/ftp.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/url.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/dict.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/if2ip.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/speedcheck.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/ldap.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/version.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/getenv.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/escape.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/mprintf.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/telnet.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/netrc.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/getinfo.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/transfer.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/strequal.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/easy.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/security.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/curl_fnmatch.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/fileinfo.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/ftplistparser.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/wildcard.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/krb5.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/memdebug.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/http_chunks.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/strtok.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/connect.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/llist.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/hash.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/multi.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/content_encoding.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/share.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/http_digest.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/md4.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/md5.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/http_negotiate.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/inet_pton.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/strtoofft.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/strerror.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/amigaos.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/hostasyn.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/hostip4.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/hostip6.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/hostsyn.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/inet_ntop.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/parsedate.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/select.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/tftp.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/splay.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/strdup.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/socks.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/ssh.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/rawstr.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/curl_addrinfo.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/socks_gssapi.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/socks_sspi.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/curl_sspi.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/slist.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/nonblock.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/curl_memrchr.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/imap.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/pop3.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/smtp.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/pingpong.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/rtsp.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/curl_threads.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/warnless.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/hmac.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/curl_rtmp.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/openldap.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/curl_gethostname.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/gopher.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/idn_win32.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/http_negotiate_sspi.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/http_proxy.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/non-ascii.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/asyn-ares.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/asyn-thread.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/curl_gssapi.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/curl_ntlm.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/curl_ntlm_wb.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/curl_ntlm_core.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/curl_ntlm_msgs.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/curl_sasl.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/curl_multibyte.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/hostcheck.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/bundles.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/conncache.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/pipeline.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/dotdot.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/x509asn1.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/http2.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/vtls/openssl.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/vtls/gtls.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/vtls/vtls.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/vtls/nss.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/vtls/qssl.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/vtls/polarssl.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/vtls/polarssl_threadlock.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/vtls/axtls.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/vtls/cyassl.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/vtls/curl_schannel.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/vtls/curl_darwinssl.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib/vtls/gskit.obj   ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib\libcurl.res
   Creating library ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib\libcurl.lib and object ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-lib\libcurl.exp
Copying libs...
    link.exe /incremental:no /libpath:"..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl\lib" /nologo /out:..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl\bin\curl.exe /subsystem:console /machine:x86 libcurl.lib ws2_32.lib wldap32.lib advapi32.lib Normaliz.lib ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl\tool_hugehelp.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl\nonblock.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl\rawstr.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl\strtoofft.obj ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_binmode.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_bname.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_cb_dbg.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_cb_hdr.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_cb_prg.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_cb_rea.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_cb_see.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_cb_wrt.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_cfgable.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_convert.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_dirhie.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_doswin.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_easysrc.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_formparse.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_getparam.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_getpass.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_help.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_helpers.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_homedir.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_libinfo.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_main.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_metalink.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_mfiles.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_msgs.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_operate.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_operhlp.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_panykey.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_paramhlp.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_parsecfg.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_setopt.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_sleep.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_urlglob.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_util.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_vms.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_writeenv.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_writeout.obj  ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl/tool_xattr.obj   ..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl-obj-curl\curl.res
tool_cb_rea.obj : error LNK2019: unresolved external symbol _curlx_read referenced in function _tool_read_cb
..\builds\libcurl-vc12-x86-release-dll-ipv6-sspi-spnego-winssl\bin\curl.exe : fatal error LNK1120: 1 unresolved externals

Answer 1

The instructions you used are actually very old. I don't know if those VS workspaces are actively maintained, and there is a newer makefile that the developers encourage people to use for command-line builds (see this thread in the curl mailing list: http://curl.haxx.se/mail/lib-2014-03/0220.html).

If you look in the curl source directory, there is a subdirectory called winbuild. I can usually build curl and libcurl successfully with the makefile in there, Makefile.vc. The options are clearly explained in the file BUILD.WINDOWS.txt. A basic build command might look something like:

C:\curl-src\winbuild> nmake -f Makefile.vc MODE=dll VC=12 MACHINE=x64

That will produce a "builds" folder in the curl source directory, which will have your curl.exe, libcurl.dll, and libcurl.lib. If you choose MODE=static, you will not get a libcurl.dll, but you will get libcurl_a.lib, which might be what you need for your project.

You can add the binaries and libs to you your VS project. You also might need to add the .h files from the curl include directory, and any other source files you want.

For curl 7.36.0, there was a small problem in the makefile, which the developers quickly corrected. You can get the updated makefiles from the GitHub repository in Daniel Stenberg's comment below. Simply replace the makefiles in the winbuild directory of the release package with the makefiles from the windbuild directory in the GitHub repo before building.

Hope that helps.