Adding None as a default value for MMTK_PLAN

Make.inc

@@ -80,6 +80,9 @@ HAVE_SSP := 0
 WITH_GC_VERIFY := 0
 WITH_GC_DEBUG_ENV := 0
 
+# Use stock if MMTK_PLAN hasn't been defined
+MMTK_PLAN ?= None
+
 # Enable DTrace support
 WITH_DTRACE := 0
 
@@ -829,7 +832,7 @@ JCXXFLAGS += -DGC_DEBUG_ENV
 JCFLAGS += -DGC_DEBUG_ENV
 endif
 
-ifneq ($(MMTK_PLAN), )
+ifneq (${MMTK_PLAN},None)
 ifeq (${MMTK_JULIA_DIR},)
 $(error MMTK_JULIA_DIR must be set to use MMTk)
 endif
@@ -1861,7 +1864,7 @@ PRINT_PERL = printf '    %b %b\n' $(PERLCOLOR)PERL$(ENDCOLOR) $(BINCOLOR)$(GOAL)
 PRINT_FLISP = printf '    %b %b\n' $(FLISPCOLOR)FLISP$(ENDCOLOR) $(BINCOLOR)$(GOAL)$(ENDCOLOR); $(1)
 PRINT_JULIA = printf '    %b %b\n' $(JULIACOLOR)JULIA$(ENDCOLOR) $(BINCOLOR)$(GOAL)$(ENDCOLOR); $(1)
 PRINT_DTRACE = printf '    %b %b\n' $(DTRACECOLOR)DTRACE$(ENDCOLOR) $(BINCOLOR)$(GOAL)$(ENDCOLOR); $(1)
-ifneq ($(MMTK_PLAN), )
+ifneq (${MMTK_PLAN},None)
 PRINT_MMTK = printf '    %b %b\n' $(LINKCOLOR)MMTK$(ENDCOLOR) $(BINCOLOR)$(GOAL)$(ENDCOLOR); $(1)
 endif
 
@@ -1874,7 +1877,7 @@ PRINT_PERL = echo '$(subst ','\'',$(1))'; $(1)
 PRINT_FLISP = echo '$(subst ','\'',$(1))'; $(1)
 PRINT_JULIA = echo '$(subst ','\'',$(1))'; $(1)
 PRINT_DTRACE = echo '$(subst ','\'',$(1))'; $(1)
-ifneq ($(MMTK_PLAN), )
+ifneq (${MMTK_PLAN},None)
 PRINT_MMTK = echo '$(subst ','\'',$(1))'; $(1)
 endif
 

src/Makefile

@@ -42,7 +42,7 @@ endif
 
 # GC source code. It depends on which GC implementation to use.
 GC_SRCS := gc-common gc-stacks gc-alloc-profiler gc-heap-snapshot
-ifneq ($(MMTK_PLAN), )
+ifneq (${MMTK_PLAN},None)
 GC_SRCS += gc-mmtk
 else
 GC_SRCS += gc-stock gc-debug gc-pages gc-page-profiler
@@ -63,7 +63,7 @@ CG_LLVMLINK :=
 ifeq ($(JULIACODEGEN),LLVM)
 # Currently these files are used by both GCs. But we should make the list specific to stock, and MMTk should have its own implementation.
 GC_CODEGEN_SRCS := llvm-final-gc-lowering llvm-late-gc-lowering llvm-gc-invariant-verifier
-ifneq ($(MMTK_PLAN), )
+ifneq (${MMTK_PLAN},None)
 FLAGS += -I$(MMTK_API_INC)
 GC_CODEGEN_SRCS += llvm-late-gc-lowering-mmtk
 else
@@ -122,7 +122,7 @@ UV_HEADERS += uv.h
 UV_HEADERS += uv/*.h
 endif
 PUBLIC_HEADERS := $(BUILDDIR)/julia_version.h $(wildcard $(SRCDIR)/support/*.h) $(addprefix $(SRCDIR)/,work-stealing-queue.h gc-interface.h gc-tls-common.h julia.h julia_assert.h julia_threads.h julia_fasttls.h julia_locks.h julia_atomics.h jloptions.h)
-ifneq ($(MMTK_PLAN), )
+ifneq (${MMTK_PLAN},None)
 	PUBLIC_HEADERS += $(addprefix $(SRCDIR)/,gc-tls-mmtk.h)
 else
 	PUBLIC_HEADERS += $(addprefix $(SRCDIR)/,gc-tls-stock.h)
@@ -250,7 +250,7 @@ $(BUILDDIR)/%.h.gen : $(SRCDIR)/%.d
 	mv $@.tmp $@
 
 # Compile files from the binding side and copy so file into lib folder
-ifneq ($(MMTK_PLAN), )
+ifneq (${MMTK_PLAN},None)
 $(MMTK_LIB_DST): $(MMTK_LIB_SRC)
 	@$(call PRINT_MMTK, cp $< $@)
 endif