diff --git a/com.oracle.truffle.r.native/Makefile b/com.oracle.truffle.r.native/Makefile
index d78f9fec754cacc46aaacc6ab3ed96f787021b4e..1cbf8fde1154a932c27e0ce651ef6236b6545723 100644
--- a/com.oracle.truffle.r.native/Makefile
+++ b/com.oracle.truffle.r.native/Makefile
@@ -21,13 +21,16 @@
 # questions.
 #
 
-.PHONY: all clean
+.PHONY: all clean makegnur cleangnur
 
 export TOPDIR = $(CURDIR)
 export R_VERSION = 3.1.3
-export GNUR_DIR = $(TOPDIR)/gnur/R-$(R_VERSION)
 
-all:
+ifndef GNUR_HOME
+export GNUR_HOME = $(TOPDIR)/gnur/R-$(R_VERSION)
+endif
+
+all: 
 	$(MAKE) -C gnur
 	$(MAKE) -C include
 	$(MAKE) -C builtinlibs
@@ -35,10 +38,11 @@ all:
 	$(MAKE) -C library
 	$(MAKE) -C run
 
-clean:
+clean: 
 	$(MAKE) -C include clean
 	$(MAKE) -C builtinlibs clean
 	$(MAKE) -C fficall clean
 	$(MAKE) -C library clean
 	$(MAKE) -C run clean
 	$(MAKE) -C gnur clean
+
diff --git a/com.oracle.truffle.r.native/builtinlibs/Makefile b/com.oracle.truffle.r.native/builtinlibs/Makefile
index 723a87ff996a88ab959e4e90d4fde44c2d1cc328..7cc6a37eb5fffb72dc6c9c3f5855bd21aac86853 100644
--- a/com.oracle.truffle.r.native/builtinlibs/Makefile
+++ b/com.oracle.truffle.r.native/builtinlibs/Makefile
@@ -40,7 +40,7 @@ OBJ = lib
 C_SOURCES := $(wildcard $(SRC)/*.c)
 
 C_OBJECTS := $(subst $(SRC),$(OBJ),$(C_SOURCES:.c=.o))
-F_OBJECTS := $(wildcard $(GNUR_DIR)/src/appl/d*.o)
+F_OBJECTS := $(wildcard $(GNUR_HOME)/src/appl/d*.o)
 
 LIBDIR := $(OBJ)
 LIB_APPL := $(OBJ)/libappl$(DYLIB_EXT)
diff --git a/com.oracle.truffle.r.native/gnur/Makefile b/com.oracle.truffle.r.native/gnur/Makefile
index 9772ef173788cd364ed4b3caf118a60fa470d51e..968ab096a09a9e76a61e5b4dd14825e05e0b0b16 100644
--- a/com.oracle.truffle.r.native/gnur/Makefile
+++ b/com.oracle.truffle.r.native/gnur/Makefile
@@ -23,12 +23,26 @@
 
 .PHONY: all clean
 
-all: 
+all: makegnur
 	$(MAKE) -f Makefile.gnur
 	$(MAKE) -f Makefile.platform
 	$(MAKE) -f Makefile.libs
 
-clean:
-	$(MAKE) -f Makefile.gnur clean
+ifeq "$(origin GNUR_HOME)" "environment"
+makegnur:
+else
+makegnur:
+	$(MAKE) -f Makefile.gnur
+endif
+
+clean: cleangnur
 	$(MAKE) -f Makefile.libs clean
 	$(MAKE) -f Makefile.platform clean
+
+ifeq "$(origin GNUR_HOME)" "environment"
+cleangnur:
+else
+cleangnur:
+	$(MAKE) -f Makefile.gnur clean
+endif
+	
\ No newline at end of file
diff --git a/com.oracle.truffle.r.native/gnur/Makefile.gnur b/com.oracle.truffle.r.native/gnur/Makefile.gnur
index 108538b086c6ca8e1a27d811fef703e16a1de343..713a88d81b49b38c7c9687a67c22dace7580cc36 100644
--- a/com.oracle.truffle.r.native/gnur/Makefile.gnur
+++ b/com.oracle.truffle.r.native/gnur/Makefile.gnur
@@ -36,9 +36,6 @@
 # Portions of the Makeconf file are then extracted to use in building the native
 # parts of FastR, especially packages with native code.
 
-# Building GnuR takes several minutes, so in some environments, e.g. repository gates,
-# referring to a pre-built GnuR would be of value. This is TBD.
-
 .PHONY: all config config_update build clean
 
 OSNAME := $(shell uname)
@@ -51,37 +48,39 @@ all:
 	@false
 endif
 
-all: Makefile $(GNUR_DIR) config build
+all: Makefile $(GNUR_HOME) config build
 
-$(GNUR_DIR): 
+$(GNUR_HOME): 
 	tar xf $(TOPDIR)/../lib/R-$(R_VERSION).tar.gz
 
-config: $(GNUR_DIR)/Makefile config_update
+config: $(GNUR_HOME)/Makefile config_update
 
 ifeq ($(OSNAME), Linux)
 config_update: Makeconf.done
 
 Makeconf.done: edMakeconf
-	ed $(GNUR_DIR)/Makeconf < edMakeconf
+	ed $(GNUR_HOME)/Makeconf < edMakeconf
 	touch Makeconf.done
 else
 config_update:
 endif
 
-$(GNUR_DIR)/Makefile:
-	(cd $(GNUR_DIR); ./configure --with-x=no --without-recommended-packages >& gnur_configure.log)
+$(GNUR_HOME)/Makefile:
+	(cd $(GNUR_HOME); ./configure --with-x=no --without-recommended-packages >& gnur_configure.log)
 
 
-build: $(GNUR_DIR)/bin/R
+build: $(GNUR_HOME)/bin/R
 
-$(GNUR_DIR)/bin/R: $(GNUR_DIR)/Makeconf 
-	(cd $(GNUR_DIR); make >& gnur_make.log)
+$(GNUR_HOME)/bin/R: $(GNUR_HOME)/Makeconf 
+	(cd $(GNUR_HOME); make >& gnur_make.log)
 
-HAVE_MAKEFILE := $(shell [ -f $(GNUR_DIR)/Makefile ] && echo "Makefile.exists")
-ifeq ($(HAVE_MAKEFILE),Makefile.exists)
-clean:
+HAVE_MAKEFILE := $(shell [ -f $(GNUR_HOME)/Makefile ] && echo "Makefile.exists")
+clean: cleangnur
 	rm -f Makeconf.done
-	(cd $(GNUR_DIR); make distclean)
+
+ifeq ($(HAVE_MAKEFILE),Makefile.exists)
+cleangnur:
+	(cd $(GNUR_HOME); make distclean)
 else
-clean:
+cleangnur:
 endif
diff --git a/com.oracle.truffle.r.native/gnur/Makefile.libs b/com.oracle.truffle.r.native/gnur/Makefile.libs
index 43739766d25a33931b64a66ecc3cf120b5b94f43..3c9a7e511b34bf6c054d0cd90bb28c9c4f91750c 100644
--- a/com.oracle.truffle.r.native/gnur/Makefile.libs
+++ b/com.oracle.truffle.r.native/gnur/Makefile.libs
@@ -37,13 +37,13 @@ all: $(TARGET_DIR) $(BLAS_TARGET) $(LAPACK_TARGET) $(PCRE_TARGET)
 $(TARGET_DIR):
 	mkdir -p $(TARGET_DIR)
 
-$(BLAS_TARGET): $(GNUR_DIR)/lib/libRblas$(DYLIB_EXT)
-	cp $(GNUR_DIR)/lib/libRblas$(DYLIB_EXT) $(BLAS_TARGET)
+$(BLAS_TARGET): $(GNUR_HOME)/lib/libRblas$(DYLIB_EXT)
+	cp $(GNUR_HOME)/lib/libRblas$(DYLIB_EXT) $(BLAS_TARGET)
 
-$(LAPACK_TARGET): $(GNUR_DIR)/lib/libRlapack$(DYLIB_EXT)
-	cp $(GNUR_DIR)/lib/libRlapack$(DYLIB_EXT) $(LAPACK_TARGET)
+$(LAPACK_TARGET): $(GNUR_HOME)/lib/libRlapack$(DYLIB_EXT)
+	cp $(GNUR_HOME)/lib/libRlapack$(DYLIB_EXT) $(LAPACK_TARGET)
 
-PCRE_OBJS := $(wildcard $(GNUR_DIR)/src/extra/pcre/pcre_*.o)
+PCRE_OBJS := $(wildcard $(GNUR_HOME)/src/extra/pcre/pcre_*.o)
 
 $(PCRE_TARGET): $(PCRE_OBJS) $(TOPDIR)/platform.mk
 	$(DYLIB_LD) $(DYLIB_LDFLAGS) -o $(PCRE_TARGET) $(PCRE_OBJS)
diff --git a/com.oracle.truffle.r.native/gnur/Makefile.platform b/com.oracle.truffle.r.native/gnur/Makefile.platform
index e38dbff2ef381be5f9fcb8146d751eb388bdd0ff..6bfbcc2619f00fc5199153cb2451a98553e7954e 100644
--- a/com.oracle.truffle.r.native/gnur/Makefile.platform
+++ b/com.oracle.truffle.r.native/gnur/Makefile.platform
@@ -31,7 +31,7 @@ OS_DIR := $(shell echo $(OS_NAME) | tr '[:upper:]' '[:lower:]' )
 all: $(TOPDIR)/platform.mk
 
 $(TOPDIR)/platform.mk: sedMakeconf
-	sed -f sedMakeconf $(GNUR_DIR)/Makeconf >& /dev/null
+	sed -f sedMakeconf $(GNUR_HOME)/Makeconf >& /dev/null
 	echo OS_NAME = $(OS_NAME) >> platform.mk.temp
 	echo OS_DIR = $(OS_DIR) >> platform.mk.temp
 	mv platform.mk.temp $(TOPDIR)/platform.mk
diff --git a/com.oracle.truffle.r.native/include/jni/Makefile b/com.oracle.truffle.r.native/include/jni/Makefile
index 77442b1d075a8046372db2c8c025afb0fab6e6e1..76829fbb97c10a7f1dec3e287dedaf5cf3dfdcb5 100644
--- a/com.oracle.truffle.r.native/include/jni/Makefile
+++ b/com.oracle.truffle.r.native/include/jni/Makefile
@@ -27,12 +27,12 @@
 
 SRC=src
 
-R_EXT_HEADERS := $(wildcard $(GNUR_DIR)/include/R_ext/*.h)
+R_EXT_HEADERS := $(wildcard $(GNUR_HOME)/include/R_ext/*.h)
 R_EXT_HEADERS_FILENAMES := $(notdir $(R_EXT_HEADERS))
 R_EXT_HEADERS_LOCAL := $(wildcard $(SRC)/R_ext/*.h)
 R_EXT_HEADERS_TO_LINK := $(filter-out $(notdir $(R_EXT_HEADERS_LOCAL)),$(R_EXT_HEADERS_FILENAMES))
 
-R_HEADERS := $(wildcard $(GNUR_DIR)/include/*.h)
+R_HEADERS := $(wildcard $(GNUR_HOME)/include/*.h)
 R_HEADERS_FILENAMES := $(notdir $(R_HEADERS))
 #$(info R_HEADERS_FILENAMES=$(R_HEADERS_FILENAMES))
 R_HEADERS_LOCAL := src/libintl.h src/Rinternals.h
@@ -45,10 +45,10 @@ all: linked
 linked:
 	mkdir -p include
 	mkdir -p include/R_ext
-	$(foreach file,$(R_HEADERS_TO_LINK),ln -sf $(GNUR_DIR)/include/$(file) include/$(file);)
+	$(foreach file,$(R_HEADERS_TO_LINK),ln -sf $(GNUR_HOME)/include/$(file) include/$(file);)
 	cp src/libintl.h include
-	ed $(GNUR_DIR)/include/Rinternals.h < ed_Rinternals
-	$(foreach file,$(R_EXT_HEADERS_TO_LINK),ln -sf $(GNUR_DIR)/include/R_ext/$(file) include/R_ext/$(file);)
+	ed $(GNUR_HOME)/include/Rinternals.h < ed_Rinternals
+	$(foreach file,$(R_EXT_HEADERS_TO_LINK),ln -sf $(GNUR_HOME)/include/R_ext/$(file) include/R_ext/$(file);)
 	cp $(R_EXT_HEADERS_LOCAL) include/R_ext
 	touch linked
 
diff --git a/com.oracle.truffle.r.native/library/lib.mk b/com.oracle.truffle.r.native/library/lib.mk
index 8a0c5b19a73b965aa0945d5314c11206c086b4ab..bf4c7e38a4728618212922ed5da3dc8d41ba7c44 100644
--- a/com.oracle.truffle.r.native/library/lib.mk
+++ b/com.oracle.truffle.r.native/library/lib.mk
@@ -39,7 +39,7 @@ endif
 
 PKG = $(PACKAGE)
 
-ifeq ($(GNUR_DIR),)
+ifeq ($(GNUR_HOME),)
 $(error must be run from top-level)
 endif
 
@@ -72,8 +72,8 @@ endif
 
 libcommon: $(PKGDIR)
 
-$(PKGDIR): $(GNUR_DIR)/library/$(PKG)
-	(cd $(GNUR_DIR)/library; tar cf - $(PKG)) | (cd $(FASTR_LIBDIR); tar xf -)
+$(PKGDIR): $(GNUR_HOME)/library/$(PKG)
+	(cd $(GNUR_HOME)/library; tar cf - $(PKG)) | (cd $(FASTR_LIBDIR); tar xf -)
 	touch $(FASTR_LIBDIR)/$(PKG)
 
 $(C_OBJECTS): | $(OBJ)
diff --git a/com.oracle.truffle.r.native/library/stats/Makefile b/com.oracle.truffle.r.native/library/stats/Makefile
index 57c77592ec6504b7e4ab34bb821c240b83f1dbc6..993a215031b6f44bca61c2c0522bf16719f6ee83 100644
--- a/com.oracle.truffle.r.native/library/stats/Makefile
+++ b/com.oracle.truffle.r.native/library/stats/Makefile
@@ -24,7 +24,7 @@
 .PHONY: cleanfft
 
 LIB_PKG_PRE = $(OBJ)/fft.o
-GNUR_FFT := $(GNUR_DIR)/src/library/stats/src/fft.c
+GNUR_FFT := $(GNUR_HOME)/src/library/stats/src/fft.c
 CLEAN_PKG := cleanfft
 
 include ../lib.mk