libgui: Enable -Weverything and -Werror

Enables -Weverything and -Werror, with just a few exceptions for
warnings we can't (or shouldn't need to) work around.

Change-Id: I034abec27bf4020d84af60d7acc1939c59986dd6
diff --git a/libs/gui/BitTube.cpp b/libs/gui/BitTube.cpp
index 3ed1f37..b653c5b 100644
--- a/libs/gui/BitTube.cpp
+++ b/libs/gui/BitTube.cpp
@@ -149,12 +149,12 @@
     ssize_t size = tube->write(vaddr, count*objSize);
 
     // should never happen because of SOCK_SEQPACKET
-    LOG_ALWAYS_FATAL_IF((size >= 0) && (size % objSize),
+    LOG_ALWAYS_FATAL_IF((size >= 0) && (size % static_cast<ssize_t>(objSize)),
             "BitTube::sendObjects(count=%zu, size=%zu), res=%zd (partial events were sent!)",
             count, objSize, size);
 
     //ALOGE_IF(size<0, "error %d sending %d events", size, count);
-    return size < 0 ? size : size / objSize;
+    return size < 0 ? size : size / static_cast<ssize_t>(objSize);
 }
 
 ssize_t BitTube::recvObjects(const sp<BitTube>& tube,
@@ -164,12 +164,12 @@
     ssize_t size = tube->read(vaddr, count*objSize);
 
     // should never happen because of SOCK_SEQPACKET
-    LOG_ALWAYS_FATAL_IF((size >= 0) && (size % objSize),
+    LOG_ALWAYS_FATAL_IF((size >= 0) && (size % static_cast<ssize_t>(objSize)),
             "BitTube::recvObjects(count=%zu, size=%zu), res=%zd (partial events were received!)",
             count, objSize, size);
 
     //ALOGE_IF(size<0, "error %d receiving %d events", size, count);
-    return size < 0 ? size : size / objSize;
+    return size < 0 ? size : size / static_cast<ssize_t>(objSize);
 }
 
 // ----------------------------------------------------------------------------