Since Github seems to have git problems at the moment, I create
this issue here. While compiling lib/curl_multibyte.c with
'-DUSE_WIN32_IDN' etc. I was getting:

  f:\mingw32\src\inet\curl\lib\memdebug.h(38): error C2054: expected '(' to follow 'CURL_EXTERN'
  f:\mingw32\src\inet\curl\lib\memdebug.h(38): error C2085: 'curl_domalloc': not in formal parameter list
  ...
  Internal Compiler Error in f:\gv\VC_2015\bin\cl.exe. You will be prompted to send an error report
  to Microsoft later.
  INTERNAL COMPILER ERROR in 'f:\gv\VC_2015\bin\cl.exe'
      Please choose the Technical Support command on the Visual C++
      Help menu, or open the Technical Support help file for more information

-----------

The fix was easy though:

--- a/curl_multibyte.c 2016-02-05 07:58:12
+++ b/curl_multibyte.c 2016-05-20 09:48:51
@@ -22,6 +22,8 @@

 #include "curl_setup.h"

+#include <curl/curl.h>
+
 #if defined(USE_WIN32_IDN) || ((defined(USE_WINDOWS_SSPI) || \
                                 defined(USE_WIN32_LDAP)) && defined(UNICODE))

-- 
--gv
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