Add a PlatformIO hook to alter CXXFLAGS

buildroot/share/PlatformIO/scripts/common-cxxflags.py

@@ -0,0 +1,12 @@
+#
+# common-cxxflags.py
+# Convenience script to apply customizations to CPP flags
+#
+Import("env")
+env.Append(CXXFLAGS=[
+  "-Wno-register"
+  #"-Wno-incompatible-pointer-types",
+  #"-Wno-unused-const-variable",
+  #"-Wno-maybe-uninitialized",
+  #"-Wno-sign-compare"
+])