Moved all c code to .h and .c files + removed struc_ prefix when not needed

macros.c

@@ -0,0 +1,7 @@
+#include <libavutil/macros.h>
+#include <stddef.h>
+
+ptrdiff_t astiavFFAlign(int i, int align)
+{
+	return FFALIGN(i, align);
+}