[Chikuzen]

g++ -o vsmatrix.dll -shared -std=c++11 -Wall -Wextra -Wno-unused-parameter -O3 -g0 -Wl,--dll,--add-stdcall-alias vsmatrix.cpp

maybe, this is OK.

EDIT:
hmm, VSHelper.h does not consider about mingw.

@@ -32,6 +32,11 @@
 #define inline _inline
 #endif
 
+#ifdef __MINGW32__
+#define __MSVCRT_VERSION__ 0x0700
+#include <malloc.h>
+#endif
+
 #ifdef _WIN32
 #define VS_ALIGNED_MALLOC(pptr, size, alignment) *(pptr) = _aligned_malloc((size), (alignment))
 #define VS_ALIGNED_FREE(ptr) _aligned_free((ptr))

you need this patch for VSHelper.h