drm_hwcomposer: build with -std=c++17 cppflag

Fixes the following building error:

external/drm_hwcomposer/DrmHwcTwo.cpp:985:14: error: decomposition declarations are a C++17 extension [-Werror,-Wc++17-extensions]
  for (auto &[handle, layer] : layers_) {
             ^~~~~~~~~~~~~~~
1 error generated.

Signed-off-by: Mauro Rossi <issor.oruam@gmail.com>
Signed-off-by: Roman Stratiienko <r.stratiienko@gmail.com>
Change-Id: I236f16969e4500ff2efb79c06500bc4d3a3d810c

1 files changed, 1 insertions, 0 deletions

diff --git a/Android.bp b/Android.bp
index 8b6d295..dd6225d 100644
--- a/Android.bp
+++ b/Android.bp
@@ -66,6 +66,7 @@ cc_defaults {
     cppflags: [
         "-DHWC2_INCLUDE_STRINGIFICATION",
         "-DHWC2_USE_CPP11",
+        "-std=c++17",
     ],
 
     product_variables: {