Rename hb_buffer_clear() to hb_buffer_clear_contents()

The previous name was clashing with harfbuzz.old.  There are systems
that need to link both...

Clash-free now again.

src/hb-buffer.cc

@@ -790,7 +790,7 @@ hb_buffer_reset (hb_buffer_t *buffer)
 }
 
 void
-hb_buffer_clear (hb_buffer_t *buffer)
+hb_buffer_clear_contents (hb_buffer_t *buffer)
 {
   buffer->clear ();
 }

src/hb-buffer.h

@@ -193,7 +193,7 @@ hb_buffer_reset (hb_buffer_t *buffer);
 
 /* Like reset, but does NOT clear unicode_funcs. */
 void
-hb_buffer_clear (hb_buffer_t *buffer);
+hb_buffer_clear_contents (hb_buffer_t *buffer);
 
 /* Returns false if allocation failed */
 hb_bool_t

test/api/test-buffer.c

@@ -135,7 +135,7 @@ test_buffer_properties (fixture_t *fixture, gconstpointer user_data)
 
   /* test clear clears all properties but unicode_funcs */
 
-  hb_buffer_clear (b);
+  hb_buffer_clear_contents (b);
 
   g_assert (hb_buffer_get_unicode_funcs (b) == ufuncs);
   g_assert (hb_buffer_get_direction (b) == HB_DIRECTION_INVALID);

util/options.hh

@@ -175,7 +175,7 @@ struct shape_options_t : option_group_t
   void populate_buffer (hb_buffer_t *buffer, const char *text, int text_len,
 			const char *text_before, const char *text_after)
   {
-    hb_buffer_clear (buffer);
+    hb_buffer_clear_contents (buffer);
     if (text_before) {
       unsigned int len = strlen (text_before);
       hb_buffer_add_utf8 (buffer, text_before, len, len, 0);