display: Fix warnings, make warnings as errors

Change-Id: I61f22765b04112be48e62135db930c415c9c7d37

common.mk

@@ -16,6 +16,8 @@ common_libs := liblog libutils libcutils libhardware
 
 #Common C flags
 common_flags := -DDEBUG_CALC_FPS -Wno-missing-field-initializers
+common_flags += -Werror
+
 ifeq ($(ARCH_ARM_HAVE_NEON),true)
     common_flags += -D__ARM_HAVE_NEON
 endif

libcopybit/copybit_c2d.cpp

@@ -446,7 +446,7 @@ static int set_image( uint32 surfaceId, const struct copybit_image_t *rhs,
         info.height = rhs->h;
         info.format = rhs->format;
 
-        yuvPlaneInfo yuvInfo;
+        yuvPlaneInfo yuvInfo = {0};
         status = calculate_yuv_offset_and_stride(info, yuvInfo);
         if(status != COPYBIT_SUCCESS) {
             ALOGE("%s: calculate_yuv_offset_and_stride error", __FUNCTION__);
@@ -701,7 +701,7 @@ static void set_rects(struct copybit_context_t *ctx,
 /** copy the bits */
 static int msm_copybit(struct copybit_context_t *dev, blitlist *list, uint32 target)
 {
-    int objects;
+    unsigned int objects;
 
     for(objects = 0; objects < list->count; objects++) {
         list->blitObjects[objects].next = &(list->blitObjects[objects+1]);

libgralloc/alloc_controller.cpp

@@ -152,7 +152,7 @@ int IonController::allocate(alloc_data& data, int usage)
 
 IMemAlloc* IonController::getAllocator(int flags)
 {
-    IMemAlloc* memalloc;
+    IMemAlloc* memalloc = NULL;
     if (flags & private_handle_t::PRIV_FLAGS_USES_ION) {
         memalloc = mIonAlloc;
     } else {

libhwcomposer/hwc_mdpcomp.cpp

@@ -343,7 +343,7 @@ bool MDPComp::is_doable(hwc_composer_device_t *dev,
     }
 
     //Number of layers
-    if(list->numHwLayers < 1 || list->numHwLayers > sMaxLayers) {
+    if(list->numHwLayers < 1 || list->numHwLayers > (uint32_t) sMaxLayers) {
         ALOGD_IF(isDebug(), "%s: Unsupported number of layers",__FUNCTION__);
         return false;
     }