buildsystem: export doc type to doxygen makefile

Makefile

@@ -6,17 +6,21 @@ all: welcome
 	@echo ""
 	@exit 1
 
+# Extract the documentation type that is to be generated and export it for
+# the doxygen Makefile
+ifneq ($(findstring doc-,$(MAKECMDGOALS)),)
+DOCUMENTATION_FORMAT := $(patsubst doc-%,%,$(filter doc-%, $(MAKECMDGOALS)))
+export DOCUMENTATION_FORMAT
+endif
+
 doc:
 	@./dist/tools/features_yaml2mx/features_yaml2mx.py \
 		features.yaml \
 		--output-md doc/doxygen/src/feature_list.md
 	"$(MAKE)" -BC doc/doxygen
 
-doc-man:
-	"$(MAKE)" -BC doc/doxygen man
-
-doc-latex:
-	"$(MAKE)" -BC doc/doxygen latex
+doc-man doc-latex:
+	"$(MAKE)" -BC doc/doxygen
 
 docclean:
 	"$(MAKE)" -BC doc/doxygen clean