From c1ad43566855c9f95b3743d9a9ce28a1d8efe6f3 Mon Sep 17 00:00:00 2001
From: Marian Buschsieweke <marian.buschsieweke@ovgu.de>
Date: Thu, 9 Jul 2020 21:19:27 +0200
Subject: [PATCH] Makefile.base: Error for C++ code w/w cpp feature

If external modules use C++ code and forget to require the `cpp` feature,
linking will still take places using $(CC). This commit adds a check if C++ code
was detected without the feature `cpp` being used, now the build is aborted
with a helpful error message rather than a linker error.
---
 Makefile.base | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Makefile.base b/Makefile.base
index d055c1a3d4..999c467240 100644
--- a/Makefile.base
+++ b/Makefile.base
@@ -63,6 +63,12 @@ ifeq ($(strip $(ASSMSRC))$(NO_AUTO_SRC),)
   ASSMSRC := $(wildcard *.S)
 endif
 
+ifneq (,$(SRCXX))
+  ifeq (,$(filter cpp,$(FEATURES_USED)))
+    $(error Found C++ source, but feature "cpp" is not used. Add "FEATURES_REQUIRED += cpp")
+  endif
+endif
+
 # include makefile snippets for packages in $(USEPKG) that modify GENSRC:
 -include $(USEPKG:%=$(RIOTPKG)/%/Makefile.gensrc)