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, 3 deletions

diff --git a/sam.h b/sam.h
index 0de831e..4c37da3 100644
--- a/sam.h
+++ b/sam.h
@@ -23,8 +23,8 @@ enum SamError {
 	SAM_ERR_COUNT,
 };
 
-bool sam_init(Vis*);
-enum SamError sam_cmd(Vis*, const char *cmd);
-const char *sam_error(enum SamError);
+VIS_INTERNAL bool sam_init(Vis*);
+VIS_INTERNAL enum SamError sam_cmd(Vis*, const char *cmd);
+VIS_INTERNAL const char *sam_error(enum SamError);
 
 #endif