diff --git a/build/premake/premake.lua b/build/premake/premake.lua
index 56cd721bdb..1119510baa 100755
--- a/build/premake/premake.lua
+++ b/build/premake/premake.lua
@@ -326,6 +326,7 @@ function setup_all_libs ()
 
 	source_dirs = {
 		"lib",
+		"lib/posix",
 		"lib/sysdep",
 		"lib/res",
 		"lib/res/file",
@@ -347,7 +348,7 @@ function setup_all_libs ()
 	sysdep_dirs = {
 		linux = { "lib/sysdep/unix" },
 		-- note: RC file must be added to main_exe package.
-		windows = { "lib/sysdep/win" },
+		windows = { "lib/sysdep/win", "lib/sysdep/win/wposix" },
 		macosx = { "lib/sysdep/osx" },
 	}
 	tinsert(package.files, sourcesfromdirs(source_root, sysdep_dirs[OS]));
diff --git a/source/lib/sysdep/win/wposix/waio.h b/source/lib/sysdep/win/wposix/waio.h
index 8346a033bf..8a0b168b28 100644
--- a/source/lib/sysdep/win/wposix/waio.h
+++ b/source/lib/sysdep/win/wposix/waio.h
@@ -90,7 +90,7 @@ extern int close(int);
 
 extern int read (int fd, void* buf, size_t nbytes);	// thunk
 extern int write(int fd, void* buf, size_t nbytes);	// thunk
-extern _CRTIMP off_t lseek(int fd, off_t ofs, int whence);
+extern "C" _CRTIMP off_t lseek(int fd, off_t ofs, int whence);
 
 
 //
diff --git a/source/lib/sysdep/win/wposix/wfilesystem.h b/source/lib/sysdep/win/wposix/wfilesystem.h
index ce941305ed..fb7992d1d5 100644
--- a/source/lib/sysdep/win/wposix/wfilesystem.h
+++ b/source/lib/sysdep/win/wposix/wfilesystem.h
@@ -89,8 +89,8 @@ extern char* realpath(const char*, char*);
 //    hence, the file is reported executable if it exists.
 #define X_OK 0
 
-extern _CRTIMP int access(const char*, int);
+extern "C" _CRTIMP int access(const char*, int);
 
-extern _CRTIMP int rmdir(const char*);
+extern "C" _CRTIMP int rmdir(const char*);
 
 #endif	// #ifndef INCLUDED_WFILESYSTEM
diff --git a/source/lib/sysdep/win/wposix/wposix_internal.h b/source/lib/sysdep/win/wposix/wposix_internal.h
index b30a5384d2..997ff8a5bc 100644
--- a/source/lib/sysdep/win/wposix/wposix_internal.h
+++ b/source/lib/sysdep/win/wposix/wposix_internal.h
@@ -17,7 +17,7 @@
 // is a last resort (e.g. if the regular CRT headers would conflict).
 #ifndef _CRTIMP
 # ifdef  _DLL
-#  define _CRTIMP extern "C" __declspec(dllimport)
+#  define _CRTIMP __declspec(dllimport)
 # else
 #  define _CRTIMP
 # endif