diff --git a/src/io.c b/src/io.c
index 36c29769..49bcfdf6 100644
--- a/src/io.c
+++ b/src/io.c
@@ -29,7 +29,7 @@
  */
 
 #include "matio_private.h"
-#if defined(_WIN32) && defined(_MSC_VER)
+#if defined(_WIN32)
 #define WIN32_LEAN_AND_MEAN
 #define NOGDI
 #include <Windows.h>
@@ -75,7 +75,7 @@ strdup_vprintf(const char *format, va_list ap)
     return buffer;
 }
 
-#if defined(_WIN32) && defined(_MSC_VER)
+#if defined(_WIN32)
 /** @brief Convert from narrow UTF-8 string to wide string
  *
  * @ingroup mat_util
diff --git a/src/mat.c b/src/mat.c
index b3845618..15bec89c 100644
--- a/src/mat.c
+++ b/src/mat.c
@@ -483,7 +483,7 @@ Mat_Open(const char *matname, int mode)
     size_t bytesread = 0;
 
     if ( (mode & 0x01) == MAT_ACC_RDONLY ) {
-#if defined(_WIN32) && defined(_MSC_VER)
+#if defined(_WIN32)
         wchar_t *wname = utf82u(matname);
         if ( NULL != wname ) {
             fp = _wfopen(wname, L"rb");
@@ -497,7 +497,7 @@ Mat_Open(const char *matname, int mode)
             return NULL;
         }
     } else if ( (mode & 0x01) == MAT_ACC_RDWR ) {
-#if defined(_WIN32) && defined(_MSC_VER)
+#if defined(_WIN32)
         wchar_t *wname = utf82u(matname);
         if ( NULL != wname ) {
             fp = _wfopen(wname, L"r+b");
@@ -1262,7 +1262,7 @@ Mat_CopyFile(const char *src, const char *dst)
     FILE *in = NULL;
     FILE *out = NULL;
 
-#if defined(_WIN32) && defined(_MSC_VER)
+#if defined(_WIN32)
     {
         wchar_t *wname = utf82u(src);
         if ( NULL != wname ) {
@@ -1278,7 +1278,7 @@ Mat_CopyFile(const char *src, const char *dst)
         return MATIO_E_FILESYSTEM_COULD_NOT_OPEN;
     }
 
-#if defined(_WIN32) && defined(_MSC_VER)
+#if defined(_WIN32)
     {
         wchar_t *wname = utf82u(dst);
         if ( NULL != wname ) {
diff --git a/src/mat4.c b/src/mat4.c
index 7fa5519d..433c2213 100644
--- a/src/mat4.c
+++ b/src/mat4.c
@@ -59,7 +59,7 @@ Mat_Create4(const char *matname)
     FILE *fp = NULL;
     mat_t *mat = NULL;
 
-#if defined(_WIN32) && defined(_MSC_VER)
+#if defined(_WIN32)
     wchar_t *wname = utf82u(matname);
     if ( NULL != wname ) {
         fp = _wfopen(wname, L"w+b");
diff --git a/src/mat5.c b/src/mat5.c
index 20795897..db19fbb7 100644
--- a/src/mat5.c
+++ b/src/mat5.c
@@ -635,7 +635,7 @@ Mat_Create5(const char *matname, const char *hdr_str)
     size_t err;
     time_t t;
 
-#if defined(_WIN32) && defined(_MSC_VER)
+#if defined(_WIN32)
     wchar_t *wname = utf82u(matname);
     if ( NULL != wname ) {
         fp = _wfopen(wname, L"w+b");
diff --git a/src/mat73.c b/src/mat73.c
index ac76be17..bf43551f 100644
--- a/src/mat73.c
+++ b/src/mat73.c
@@ -2548,7 +2548,7 @@ Mat_Create73(const char *matname, const char *hdr_str)
     H5Fclose(fid);
     H5Pclose(plist_id);
 
-#if defined(_WIN32) && defined(_MSC_VER) && H5_VERSION_GE(1, 11, 6)
+#if defined(_WIN32) && H5_VERSION_GE(1, 11, 6)
     {
         wchar_t *wname = utf82u(matname);
         if ( NULL != wname ) {
diff --git a/src/matio_private.h b/src/matio_private.h
index afbf71f0..395e1659 100644
--- a/src/matio_private.h
+++ b/src/matio_private.h
@@ -41,18 +41,19 @@
 #endif
 
 #if defined(__BORLANDC__) || defined(__MINGW32__) || defined(_MSC_VER)
-#define mat_off_t __int64
 #if defined(_MSC_VER) && defined(HAVE__FSEEKI64) && defined(HAVE__FTELLI64)
 #define MATIO_LFS
+#define mat_off_t __int64
 #define fseeko _fseeki64
 #define ftello _ftelli64
 #elif defined(__BORLANDC__) && defined(HAVE__FSEEKI64) && defined(HAVE__FTELLI64)
 #define MATIO_LFS
+#define mat_off_t __int64
 #define fseeko _fseeki64
 #define ftello _ftelli64
-#elif !defined(HAVE_FSEEKO) && !defined(HAVE_FTELLO) && defined(HAVE_FSEEKO64) && \
-    defined(HAVE_FTELLO64)
+#elif defined(HAVE_FSEEKO64) && defined(HAVE_FTELLO64)
 #define MATIO_LFS
+#define mat_off_t __int64
 #define fseeko fseeko64
 #define ftello ftello64
 #endif
@@ -266,7 +267,7 @@ EXTERN int IsEndOfFile(FILE *fp, mat_off_t *fpos);
 EXTERN int CheckSeekFile(FILE *fp, mat_off_t offset);
 
 /* io.c */
-#if defined(_WIN32) && defined(_MSC_VER)
+#if defined(_WIN32)
 EXTERN wchar_t *utf82u(const char *src);
 #endif