grDevices: omit non-Mac files on Linux

com.oracle.truffle.r.native/library/grDevices/Makefile

@@ -21,6 +21,14 @@
 # questions.
 #
 
+ifneq (,$(wildcard $(TOPDIR)/platform.mk))
+include $(TOPDIR)/platform.mk
+else
+ifneq ($(MAKECMDGOALS),clean)
+$(error no platform.mk available)
+endif
+endif
+
 OBJ = lib
 
 GNUR_INCLUDES := -I$(TOPDIR)/fficall/src/include
@@ -30,7 +38,11 @@ GNUR_SRC_CAIRO := $(GNUR_HOME)/src/library/grDevices/src/cairo
 GNUR_CAIRO_C_SOURCES := $(notdir $(wildcard $(GNUR_SRC_CAIRO)/*.c))
 # not compiling Cairo currently
 GNUR_C_SOURCES := axis_scales.c chull.c colors.c devCairo.c devPS.c devPicTeX.c devQuartz.c \
-                devices.c init.c qdBitmap.c qdPDF.c stubs.c # $(GNUR_CAIRO_C_SOURCES)
+                devices.c init.c stubs.c
+
+ifeq ($(OS_NAME), Darwin)
+GNUR_C_SOURCES := $(GNUR_C_SOURCES) qdBitmap.c qdPDF.c
+endif
 
 GNUR_C_OBJECTS := $(addprefix $(OBJ)/, $(GNUR_C_SOURCES:.c=.o))