removed GapBuffer_getByteCount prototype from header

gap_buffer.c

@@ -27,8 +27,11 @@ struct GapBuffer {
 ** Notes:
 **   - This information isn't very useful to the owner
 **     of the gap instance. It's only really used while
-**     testing. It may be good to make it private to the
-**     testing routine somehow.
+**     testing.
+**
+**   - This isn't declared in the header file, so
+**     if a program wants to use this function it need
+**     to specify its prototype explicitly.
 */
 size_t GapBuffer_getByteCount(GapBuffer *buff)
 {

gap_buffer.h

@@ -27,7 +27,6 @@ void       GapBuffer_moveRelative(GapBuffer *buff, int off);
 void       GapBuffer_moveAbsolute(GapBuffer *buff, size_t num);
 void       GapBuffer_removeForwards(GapBuffer *buff, size_t num);
 void       GapBuffer_removeBackwards(GapBuffer *buff, size_t num);
-size_t     GapBuffer_getByteCount(GapBuffer *buff);
 void       GapBufferIter_init(GapBufferIter *iter, GapBuffer *buff);
 void       GapBufferIter_free(GapBufferIter *iter);
 bool       GapBufferIter_next(GapBufferIter *iter, GapBufferLine *line);