mark all functions in headers with VIS_EXPORT or VIS_INTERNAL

if vis actually wants to be a library exported symbols may need
mark up depending on the platform (eg. __declspec(dllexport)).
This needs to be hidden behind a macro because the way you export
is not the same on every platform.

I did this based on the assumption that vis.h was supposed to be
the only interface to the "vis" library. Since nobody actually
uses vis as a library I have no idea if this is actually correct.

Anyway marking up all prototypes like this allows for one to
convert all functions to static if a single translation unit is
used by inserting at the start:

 #define VIS_INTERNAL static
 #define VIS_EXPORT   static

1 files changed, 3 insertions, 2 deletions

diff --git a/test/core/array-test.c b/test/core/array-test.c
index 72a6678..e4da4f6 100644
--- a/test/core/array-test.c
+++ b/test/core/array-test.c
@@ -4,9 +4,10 @@
 #include <string.h>
 #include <stdio.h>
 #include <errno.h>
+
 #include "tap.h"
-#include "array.h"
-#include "util.h"
+
+#include "array.c"
 
 typedef struct {
 	char key[64];