added code from gh

Firmware/lib/json11/Makefile

@@ -0,0 +1,15 @@
+# Environment variable to enable or disable code which demonstrates the behavior change
+# in Xcode 7 / Clang 3.7, introduced by DR1467 and described here:
+# https://llvm.org/bugs/show_bug.cgi?id=23812
+# Defaults to on in order to act as a warning to anyone who's unaware of the issue.
+ifneq ($(JSON11_ENABLE_DR1467_CANARY),)
+CANARY_ARGS = -DJSON11_ENABLE_DR1467_CANARY=$(JSON11_ENABLE_DR1467_CANARY)
+endif
+
+test: json11.cpp json11.hpp test.cpp
+	$(CXX) $(CANARY_ARGS) -O -std=c++11 json11.cpp test.cpp -o test -fno-rtti -fno-exceptions
+
+clean:
+	if [ -e test ]; then rm test; fi
+
+.PHONY: clean