tests/pkg/emlearn: add model.h to repo

The Makefile rule to regenerate model.h has been left in place, but
just adding the header to the test allows to build the application
without heaving emlearn installed, which is convenient for the CI.

Actual users of emlearn will like still want to generate the header.

tests/pkg/emlearn/.gitignore

@@ -1,2 +1,4 @@
-model.h
 tmp/
+/model_head.h
+/model_tail.h
+/tmp.h

tests/pkg/emlearn/Makefile

@@ -8,6 +8,21 @@ BUILDDEPS += model.h
 
 include $(RIOTBASE)/Makefile.include
 
-model.h: $(CURDIR)/model
+model_head.h:
+	$(Q)echo "#ifndef MODEL_H" > model_head.h
+	$(Q)echo "#define MODEL_H" >> model_head.h
+	$(Q)echo "#ifdef __cplusplus" >> model_head.h
+	$(Q)echo "extern \"C\" {" >> model_head.h
+	$(Q)echo "#endif" >> model_head.h
+
+model_tail.h:
+	$(Q)echo "#ifdef __cplusplus" > model_tail.h
+	$(Q)echo "}" >> model_tail.h
+	$(Q)echo "#endif" >> model_tail.h
+	$(Q)echo "#endif /* MODEL_H */" >> model_tail.h
+
+model.h: $(CURDIR)/model model_head.h model_tail.h
 	$(Q)$(CURDIR)/generate_model.py
-	$(Q)echo "/* fix for no newline at eof */" >> model.h
+	$(Q)sed -i model.h -e 's/[\t ]*$$//g'
+	$(Q)cat model_head.h model.h model_tail.h > tmp.h
+	$(Q)mv tmp.h model.h