Create libgfx, starting with FloatRect

Creates libgfx, the future home of everything currently in libui and
libgui, which will be rigorously checked with -Weverything (with a few
common-sense exceptions) and clang-tidy and formatted using the included
.clang-format file.

Starts by moving FloatRect out of services/surfaceflinger since it will
be used by other libgfx primitives later.

Test: m
Change-Id: I5045ac089020e6ee380e81e8735117c500264b37
diff --git a/vulkan/libvulkan/Android.bp b/vulkan/libvulkan/Android.bp
index 5a0a93b..f1c4c83 100644
--- a/vulkan/libvulkan/Android.bp
+++ b/vulkan/libvulkan/Android.bp
@@ -46,6 +46,7 @@
         "-Wno-c99-extensions",
         "-Wno-c++98-compat-pedantic",
         "-Wno-exit-time-destructors",
+        "-Wno-float-equal",
         "-Wno-global-constructors",
         "-Wno-zero-length-array",
     ],