Fix Mac compile again

Author: mdboom

src/_path_wrapper.cpp

@@ -1,3 +1,5 @@
+#include "numpy_cpp.h"
+
 #include "_path.h"
 
 #include "py_converters.h"

src/_png.cpp

@@ -12,6 +12,11 @@
 
 #include <vector>
 
+#include "numpy_cpp.h"
+#include "mplutils.h"
+#include "file_compat.h"
+
+extern "C" {
 #ifdef __linux__
 #   include <png.h>
 #   ifdef _POSIX_C_SOURCE
@@ -28,10 +33,8 @@
 
 #   include <png.h>
 #endif
+}
 
-#include "file_compat.h"
-#include "numpy_cpp.h"
-#include "mplutils.h"
 
 // As reported in [3082058] build _png.so on aix
 #ifdef _AIX

src/mplutils.h

@@ -5,7 +5,7 @@
 #ifndef _MPLUTILS_H
 #define _MPLUTILS_H
 
-#ifdef _MSC_VER && _MSC_VER <= 1600
+#if defined(_MSC_VER) && _MSC_VER <= 1600
 typedef unsigned __int8   uint8_t;
 #else
 #include <stdint.h>