add C linkage for C++ codebase

glview.c

@@ -1,11 +1,12 @@
 #include <SDL/SDL.h>
 #ifdef __APPLE__
 #include <OpenGL/gl.h>
+#include <stdlib.h>
 #else
 #include <GL/gl.h>
+#include <malloc.h>
 #endif
 #include <stdio.h>
-#include <malloc.h>
 
 #include "upng.h"
 

png2tga.c

@@ -1,5 +1,9 @@
 #include <stdio.h>
+#ifdef __APPLE__
+#include <stdlib.h>
+#else
 #include <malloc.h>
+#endif
 
 #include "upng.h"
 

upng.c

@@ -23,7 +23,10 @@ freely, subject to the following restrictions:
 		3. This notice may not be removed or altered from any source
 		distribution.
 */
-
+#ifdef __cplusplus
+extern "C"
+{
+#endif
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -1279,3 +1282,6 @@ unsigned upng_get_size(const upng_t* upng)
 {
 	return upng->size;
 }
+#ifdef __cplusplus
+}
+#endif

upng.h

@@ -27,6 +27,11 @@ freely, subject to the following restrictions:
 #if !defined(UPNG_H)
 #define UPNG_H
 
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
 typedef enum upng_error {
 	UPNG_EOK			= 0, /* success (no error) */
 	UPNG_ENOMEM			= 1, /* memory allocation failed */
@@ -78,4 +83,9 @@ upng_format	upng_get_format		(const upng_t* upng);
 const unsigned char*	upng_get_buffer		(const upng_t* upng);
 unsigned				upng_get_size		(const upng_t* upng);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /*defined(UPNG_H)*/
+