Use -Werror in system/core/libpixelflinger

* Remove unused local variables.
* Suppress/fix warning of unused functions, conditionally used variables.

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: If92bc79f15a0486364da0389defbb2d43b3bd6ea
diff --git a/libpixelflinger/codeflinger/texturing.cpp b/libpixelflinger/codeflinger/texturing.cpp
index 4c357af..e6997bd 100644
--- a/libpixelflinger/codeflinger/texturing.cpp
+++ b/libpixelflinger/codeflinger/texturing.cpp
@@ -41,7 +41,6 @@
 void GGLAssembler::init_iterated_color(fragment_parts_t& parts, const reg_t& x)
 {
     context_t const* c = mBuilderContext.c;
-    const needs_t& needs = mBuilderContext.needs;
 
     if (mSmooth) {
         // NOTE: we could take this case in the mDithering + !mSmooth case,
@@ -324,9 +323,7 @@
         tex_coord_t* coords,
         const reg_t& x, const reg_t& y)
 {
-    context_t const* c = mBuilderContext.c;
     const needs_t& needs = mBuilderContext.needs;
-    int Rctx = mBuilderContext.Rctx;
     int Rx = x.reg;
     int Ry = y.reg;
 
@@ -402,10 +399,6 @@
 void GGLAssembler::build_textures(  fragment_parts_t& parts,
                                     Scratch& regs)
 {
-    context_t const* c = mBuilderContext.c;
-    const needs_t& needs = mBuilderContext.needs;
-    int Rctx = mBuilderContext.Rctx;
-
     // We don't have a way to spill registers automatically
     // spill depth and AA regs, when we know we may have to.
     // build the spill list...
@@ -434,7 +427,6 @@
 
     Spill spill(registerFile(), *this, spill_list);
 
-    const bool multiTexture = mTextureMachine.activeUnits > 1;
     for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT; i++) {
         const texture_unit_t& tmu = mTextureMachine.tmu[i];
         if (tmu.format_idx == 0)
@@ -442,7 +434,7 @@
 
         pointer_t& txPtr = parts.coords[i].ptr;
         pixel_t& texel = parts.texel[i];
-            
+
         // repeat...
         if ((tmu.swrap == GGL_NEEDS_WRAP_11) &&
             (tmu.twrap == GGL_NEEDS_WRAP_11))
@@ -656,7 +648,6 @@
 void GGLAssembler::build_iterate_texture_coordinates(
     const fragment_parts_t& parts)
 {
-    const bool multiTexture = mTextureMachine.activeUnits > 1;
     for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT; i++) {
         const texture_unit_t& tmu = mTextureMachine.tmu[i];
         if (tmu.format_idx == 0)