Protect against multiple inclusion of Makefile.base.mk

Signed-off-by: falkTX <falktx@falktx.com>

Makefile.base.mk

@@ -8,6 +8,13 @@ AR  ?= ar
 CC  ?= gcc
 CXX ?= g++
 
+# ---------------------------------------------------------------------------------------------------------------------
+# Protect against multiple inclusion
+
+ifneq ($(DPF_MAKEFILE_BASE_INCLUDED),true)
+
+DPF_MAKEFILE_BASE_INCLUDED = true
+
 # ---------------------------------------------------------------------------------------------------------------------
 # Auto-detect OS if not defined
 
@@ -487,3 +494,8 @@ features:
 	$(call print_available,HAVE_XRANDR)
 
 # ---------------------------------------------------------------------------------------------------------------------
+# Protect against multiple inclusion
+
+endif # DPF_MAKEFILE_BASE_INCLUDED
+
+# ---------------------------------------------------------------------------------------------------------------------