diff --git a/Makefile.msvc b/Makefile.msvc
index 99d2630..7bd90eb 100644
--- a/Makefile.msvc
+++ b/Makefile.msvc
@@ -3,7 +3,7 @@ CXXC = cl
 LINK=link
 CFLAGS = /O2 /GA /GL /Gy /Oi /Ob2 /nologo /W3 /EHsc /MT /wd4244
 LDFLAGS = /link /OPT:REF /OPT:ICF /LTCG /NXCOMPAT /DYNAMICBASE ADVAPI32.LIB
-DEFS =  -D_CRT_SECURE_NO_DEPRECATE -DDLL_EXPORT \
+DEFS =  -D_CRT_SECURE_NO_DEPRECATE -DCRFPP_DLL -DCRFPP_DLL_EXPORT -DDLL_EXPORT \
         -DUNICODE -D_UNICODE \
         -DHAVE_WINDOWS_H -DVERSION="\"0.59\"" -DPACKAGE="\"CRF++\""
 INC = -I. -I..
diff --git a/common.h b/common.h
index 4269227..a340d06 100644
--- a/common.h
+++ b/common.h
@@ -18,7 +18,9 @@
 #include <cmath>
 
 #if defined(_WIN32) && !defined(__CYGWIN__)
-#define NOMINMAX
+#ifndef NOMINMAX
+#  define NOMINMAX
+#endif
 #include <windows.h>
 #endif
 
@@ -180,7 +182,7 @@ std::wstring Utf8ToWide(const std::string &input);
 std::string WideToUtf8(const std::wstring &input);
 #endif
 
-#if defined(_WIN32) && !defined(__CYGWIN__)
+#if defined(_WIN32) && !defined(__CYGWIN__) && !defined(__MINGW32__)
 #define WPATH(path) (CRFPP::Utf8ToWide(path).c_str())
 #else
 #define WPATH(path) (path)
@@ -210,10 +212,11 @@ class string_buffer: public std::string {
   string_buffer& operator<<(short int _n)          { _ITOA(_n); }
   string_buffer& operator<<(int _n)                { _ITOA(_n); }
   string_buffer& operator<<(long int _n)           { _ITOA(_n); }
+  string_buffer& operator<<(long long _n)          { _ITOA(_n); }
   string_buffer& operator<<(unsigned short int _n) { _UITOA(_n); }
   string_buffer& operator<<(unsigned int _n)       { _UITOA(_n); }
-  //  string_buffer& operator<<(unsigned long int _n)  { _UITOA(_n); }
-  string_buffer& operator<<(size_t _n)             { _UITOA(_n); }
+  string_buffer& operator<<(unsigned long int _n)  { _UITOA(_n); }
+  string_buffer& operator<<(unsigned long long _n) { _UITOA(_n); }
   string_buffer& operator<<(char _n) {
     push_back(_n);
     return *this;
diff --git a/crfpp.h b/crfpp.h
index aa2dbda..f9b1aeb 100644
--- a/crfpp.h
+++ b/crfpp.h
@@ -20,12 +20,14 @@ extern "C" {
 #endif
 
 #ifdef _WIN32
-#include <windows.h>
-#  ifdef DLL_EXPORT
-#    define CRFPP_DLL_EXTERN  __declspec(dllexport)
-#    define CRFPP_DLL_CLASS_EXTERN  __declspec(dllexport)
-#  else
-#    define CRFPP_DLL_EXTERN  __declspec(dllimport)
+#  include <windows.h>
+#  ifdef CRFPP_DLL
+#    ifdef CRFPP_DLL_EXPORT
+#      define CRFPP_DLL_EXTERN  __declspec(dllexport)
+#      define CRFPP_DLL_CLASS_EXTERN  __declspec(dllexport)
+#    else
+#      define CRFPP_DLL_EXTERN  __declspec(dllimport)
+#    endif
 #  endif
 #endif
 
diff --git a/encoder.cpp b/encoder.cpp
index 2c6f758..e2a0be2 100644
--- a/encoder.cpp
+++ b/encoder.cpp
@@ -10,7 +10,9 @@
 #endif
 
 #if defined(_WIN32) && !defined(__CYGWIN__)
-#define NOMINMAX
+#ifndef NOMINMAX
+#  define NOMINMAX
+#endif
 #include <windows.h>
 #endif
 
diff --git a/mmap.h b/mmap.h
index 22cb378..ebe3bcc 100644
--- a/mmap.h
+++ b/mmap.h
@@ -105,7 +105,8 @@ template <class T> class Mmap {
       CHECK_FALSE(false) << "unknown open mode:" << filename;
     }
 
-    hFile = ::CreateFileW(WPATH(filename), mode1, FILE_SHARE_READ, 0,
+    std::wstring wpath = Utf8ToWide(filename);
+    hFile = ::CreateFileW(wpath.c_str(), mode1, FILE_SHARE_READ, 0,
                           OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
     CHECK_FALSE(hFile != INVALID_HANDLE_VALUE)
         << "CreateFile() failed: " << filename;