diff --git a/pio-tools/add_c_flags.py b/pio-tools/add_c_flags.py
new file mode 100644
index 000000000..c93059b36
--- /dev/null
+++ b/pio-tools/add_c_flags.py
@@ -0,0 +1,4 @@
+Import("env")
+
+# General options that are passed to the C compiler (C only; not C++).
+env.Append(CFLAGS=["-Wno-discarded-qualifiers"])