stagefright amrwbenc: Make the mem_malloc function 64-bit safe

Change-Id: Iab0dbfdc6be09c62d353bee46596635686b784a6
diff --git a/media/libstagefright/codecs/amrwbenc/src/mem_align.c b/media/libstagefright/codecs/amrwbenc/src/mem_align.c
index a29baf3..3b7853f 100644
--- a/media/libstagefright/codecs/amrwbenc/src/mem_align.c
+++ b/media/libstagefright/codecs/amrwbenc/src/mem_align.c
@@ -23,6 +23,11 @@
 
 
 #include	"mem_align.h"
+#ifdef _MSC_VER
+#include	<stddef.h>
+#else
+#include	<stdint.h>
+#endif
 
 /*****************************************************************************
 *
@@ -66,8 +71,8 @@
 		pMemop->Set(CodecID, tmp, 0, size + alignment);
 
 		mem_ptr =
-			(unsigned char *) ((unsigned int) (tmp + alignment - 1) &
-					(~((unsigned int) (alignment - 1))));
+			(unsigned char *) ((intptr_t) (tmp + alignment - 1) &
+					(~((intptr_t) (alignment - 1))));
 
 		if (mem_ptr == tmp)
 			mem_ptr += alignment;