Given this C:

#include <stdio.h>

__declspec(dllexport) int
RegisterClient2(int *pnClientId, const char *pszIPAddress) {
    printf( "id:%d  addr: %s\n", *pnClientId, pszIPAddress );
    return 12345;
}
[download]

Compiled to a DLL like this:

C:\test>cl /LD /MT 853196dll.c
Microsoft (R) C/C++ Optimizing Compiler Version 15.00.21022.08 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

853196dll.c
Microsoft (R) Incremental Linker Version 9.00.21022.08
Copyright (C) Microsoft Corporation.  All rights reserved.

/out:853196dll.dll
/dll
/implib:853196dll.lib
853196dll.obj
   Creating library 853196dll.lib and object 853196dll.exp
[download]

And this Inline::C:

#! perl -slw
use strict;
use Inline C => Config => BUILD_NOISY => 1, LIBS => 'c:\test\853196dll
+.lib';
use Inline C => <<'END_C',  NAME => '_853198_IC', CLEAN_AFTER_BUILD =>
+ 0;

int RegClient( SV *id, SV *IP ) {
    int c_id = SvIV( id );
    char *c_ip = SvPVX( IP );
    return RegisterClient2( &c_id, c_ip );
}

END_C

print RegClient( 123, 'fred' );
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Running the Perl code gives:

C:\test>853196-ic.pl
Starting Build Preprocess Stage
Finished Build Preprocess Stage

Starting Build Parse Stage
Finished Build Parse Stage

Starting Build Glue 1 Stage
Finished Build Glue 1 Stage

Starting Build Glue 2 Stage
Finished Build Glue 2 Stage

Starting Build Glue 3 Stage
Finished Build Glue 3 Stage

Starting Build Compile Stage
  Starting "perl Makefile.PL" Stage
Writing Makefile for _853198_IC
  Finished "perl Makefile.PL" Stage

  Starting "make" Stage

Microsoft (R) Program Maintenance Utility Version 9.00.21022.08
Copyright (C) Microsoft Corporation.  All rights reserved.

        C:\Perl64\bin\perl.exe C:\Perl64\lib\ExtUtils\xsubpp  -typem
        cl -c  -IC:/test  -nologo -GF -W3 -MD -Zi -DNDEBUG -Ox -GL 
_853198_IC.c
_853198_IC.xs(7) : warning C4244: 'initializing' : conversion from '
_853198_IC.xs(9) : warning C4013: 'RegisterClient2' undefined; assum
Running Mkbootstrap for _853198_IC ()
        C:\Perl64\bin\perl.exe -MExtUtils::Command -e "chmod" -- 644
        C:\Perl64\bin\perl.exe -MExtUtils::Mksymlists  -e "Mksymlists
        link -out:blib\arch\auto\_853198_IC\_853198_IC.dll -dll -nolo
2.lib" "C:\Program Files\Microsoft SDKs\Windows\v6.1\Lib\X64\winspool
rosoft SDKs\Windows\v6.1\Lib\X64\uuid.lib" "C:\Program Files\Microsof
\Microsoft Visual Studio 9.0\VC\Lib\amd64\msvcrt.lib" -def:_853198_IC
   Creating library blib\arch\auto\_853198_IC\_853198_IC.lib and obje
Generating code
Finished generating code
        if exist blib\arch\auto\_853198_IC\_853198_IC.dll.manifest mt
        if exist blib\arch\auto\_853198_IC\_853198_IC.dll.manifest de
        C:\Perl64\bin\perl.exe -MExtUtils::Command -e "chmod" -- 755
        C:\Perl64\bin\perl.exe -MExtUtils::Command -e "cp" -- _85319
        C:\Perl64\bin\perl.exe -MExtUtils::Command -e "chmod" -- 644 
  Finished "make" Stage

  Starting "make install" Stage

Microsoft (R) Program Maintenance Utility Version 9.00.21022.08
Copyright (C) Microsoft Corporation.  All rights reserved.

Files found in blib\arch: installing files in blib\lib into architectu
+re 
Installing C:\test\_Inline\lib\auto\_853198_IC\_853198_IC.dll
Installing C:\test\_Inline\lib\auto\_853198_IC\_853198_IC.exp
Installing C:\test\_Inline\lib\auto\_853198_IC\_853198_IC.lib
Installing C:\test\_Inline\lib\auto\_853198_IC\_853198_IC.pdb
  Finished "make install" Stage

  Starting Cleaning Up Stage
  Finished Cleaning Up Stage

Finished Build Compile Stage

id:123  addr: fred
12345
[download]

Whether you can adapt that to work with MinGW, and no .lib I don't know.