Replace gl_frag_attrib enum with gl_varying_slot.

This patch makes the following search-and-replace changes:

gl_frag_attrib -> gl_varying_slot
FRAG_ATTRIB_* -> VARYING_SLOT_*
FRAG_BIT_* -> VARYING_BIT_*

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Tested-by: Brian Paul <brianp@vmware.com>

src/mesa/program/program_parse.y

@@ -1187,19 +1187,19 @@ vtxWeightNum: INTEGER;
 
 fragAttribItem: POSITION
 	{
-	   $$ = FRAG_ATTRIB_WPOS;
+	   $$ = VARYING_SLOT_POS;
 	}
 	| COLOR optColorType
 	{
-	   $$ = FRAG_ATTRIB_COL0 + $2;
+	   $$ = VARYING_SLOT_COL0 + $2;
 	}
 	| FOGCOORD
 	{
-	   $$ = FRAG_ATTRIB_FOGC;
+	   $$ = VARYING_SLOT_FOGC;
 	}
 	| TEXCOORD optTexCoordUnitNum
 	{
-	   $$ = FRAG_ATTRIB_TEX0 + $2;
+	   $$ = VARYING_SLOT_TEX0 + $2;
 	}
 	;