diff --git a/source/lib/sysdep/win/win_internal.h b/source/lib/sysdep/win/win_internal.h
index d28f45a02c..094fd235a5 100755
--- a/source/lib/sysdep/win/win_internal.h
+++ b/source/lib/sysdep/win/win_internal.h
@@ -238,11 +238,22 @@ typedef struct _SYSTEM_POWER_INFORMATION
 
 #include "types.h"	// intptr_t
 
+
+/* Define _CRTIMP */
+
+#ifndef _CRTIMP
+#ifdef  _DLL
+#define _CRTIMP __declspec(dllimport)
+#else   /* ndef _DLL */
+#define _CRTIMP
+#endif  /* _DLL */
+#endif  /* _CRTIMP */
+
 extern "C" {
-extern intptr_t _get_osfhandle(int);
-extern int _open_osfhandle(intptr_t, int);
-extern int _open(const char* fn, int mode, ...);
-extern int _close(int);
+_CRTIMP intptr_t _get_osfhandle(int);
+_CRTIMP int _open_osfhandle(intptr_t, int);
+_CRTIMP int _open(const char* fn, int mode, ...);
+_CRTIMP int _close(int);
 
 #ifndef NO_WINSOCK
 extern __declspec(dllimport) int __stdcall WSAStartup(unsigned short, void*);
diff --git a/source/lib/sysdep/win/wposix.h b/source/lib/sysdep/win/wposix.h
index 04a0b53f8d..932adc1602 100755
--- a/source/lib/sysdep/win/wposix.h
+++ b/source/lib/sysdep/win/wposix.h
@@ -33,6 +33,17 @@ extern "C" {
 #endif
 
 
+
+/* Define _CRTIMP */
+
+#ifndef _CRTIMP
+#ifdef  _DLL
+#define _CRTIMP __declspec(dllimport)
+#else   /* ndef _DLL */
+#define _CRTIMP
+#endif  /* _DLL */
+#endif  /* _CRTIMP */
+
 //
 // <inttypes.h>
 //
@@ -211,7 +222,7 @@ extern int munmap(void* start, size_t len);
 
 #define O_NONBLOCK     0x1000000
 
-extern int open(const char* fn, int mode, ...);
+_CRTIMP int open(const char* fn, int mode, ...);
 
 
 //
@@ -229,12 +240,12 @@ extern int open(const char* fn, int mode, ...);
 #define read _read
 #define write _write
 
-extern int close(int);
-extern int access(const char*, int);
+_CRTIMP int close(int);
+_CRTIMP int access(const char*, int);
 
 extern int chdir(const char*);
 #define getcwd _getcwd
-extern char* getcwd(char*, int);
+_CRTIMP char* getcwd(char*, int);
 
 // user tests if available via #ifdef; can't use enum.
 #define _SC_PAGESIZE      1