this should probably be part of spawn, if it is needed

Makefile

@@ -154,8 +154,7 @@ $(build_depsbindir)/stringreplace: $(JULIAHOME)/contrib/stringreplace.c | $(buil
 	@$(call PRINT_CC, $(HOSTCC) -o $(build_depsbindir)/stringreplace $(JULIAHOME)/contrib/stringreplace.c)
 
 julia-base-cache: julia-sysimg-$(JULIA_BUILD_MODE) | $(DIRS) $(build_datarootdir)/julia
-	@JULIA_BINDIR=$(call cygpath_w,$(build_bindir)) WINEPATH="$(call cygpath_w,$(build_bindir));$$WINEPATH" \
-		$(call spawn, $(JULIA_EXECUTABLE) --startup-file=no $(call cygpath_w,$(JULIAHOME)/etc/write_base_cache.jl) \
+	@JULIA_BINDIR=$(call cygpath_w,$(build_bindir)) $(call spawn, $(JULIA_EXECUTABLE) --startup-file=no $(call cygpath_w,$(JULIAHOME)/etc/write_base_cache.jl) \
 		$(call cygpath_w,$(build_datarootdir)/julia/base.cache))
 
 # public libraries, that are installed in $(prefix)/lib

sysimage.mk

@@ -65,8 +65,7 @@ $(build_private_libdir)/corecompiler.ji: $(COMPILER_SRCS)
 
 $(build_private_libdir)/sys.ji: $(build_private_libdir)/corecompiler.ji $(JULIAHOME)/VERSION $(BASE_SRCS) $(STDLIB_SRCS)
 	@$(call PRINT_JULIA, cd $(JULIAHOME)/base && \
-	if ! JULIA_BINDIR=$(call cygpath_w,$(build_bindir)) WINEPATH="$(call cygpath_w,$(build_bindir));$$WINEPATH" \
-			$(call spawn, $(JULIA_EXECUTABLE)) -g1 -O0 -C "$(JULIA_CPU_TARGET)" --output-ji $(call cygpath_w,$@).tmp $(JULIA_SYSIMG_BUILD_FLAGS) \
+	if ! JULIA_BINDIR=$(call cygpath_w,$(build_bindir)) $(call spawn, $(JULIA_EXECUTABLE)) -g1 -O0 -C "$(JULIA_CPU_TARGET)" --output-ji $(call cygpath_w,$@).tmp $(JULIA_SYSIMG_BUILD_FLAGS) \
 			--startup-file=no --warn-overwrite=yes --sysimage $(call cygpath_w,$<) sysimg.jl $(RELBUILDROOT); then \
 		echo '*** This error might be fixed by running `make clean`. If the error persists$(COMMA) try `make cleanall`. ***'; \
 		false; \
@@ -76,9 +75,8 @@ $(build_private_libdir)/sys.ji: $(build_private_libdir)/corecompiler.ji $(JULIAH
 define sysimg_builder
 $$(build_private_libdir)/sys$1-o.a $$(build_private_libdir)/sys$1-bc.a : $$(build_private_libdir)/sys$1-%.a : $$(build_private_libdir)/sys.ji
 	@$$(call PRINT_JULIA, cd $$(JULIAHOME)/base && \
-	if ! JULIA_BINDIR=$$(call cygpath_w,$(build_bindir)) WINEPATH="$(call cygpath_w,$(build_bindir));$$WINEPATH" \
-			$$(call spawn, $3) $2 -C "$$(JULIA_CPU_TARGET)" --output-$$* $$(call cygpath_w,$$@).tmp $$(JULIA_SYSIMG_BUILD_FLAGS) \
-			--startup-file=no --warn-overwrite=yes --sysimage $$(call cygpath_w,$$<) $$(call cygpath_w,$$(JULIAHOME)/contrib/generate_precompile.jl) $(JULIA_PRECOMPILE); then \
+	if ! JULIA_BINDIR=$$(call cygpath_w,$(build_bindir)) $$(call spawn, $3) $2 -C "$$(JULIA_CPU_TARGET)" --output-$$* $$(call cygpath_w,$$@).tmp $$(JULIA_SYSIMG_BUILD_FLAGS) \
+		--startup-file=no --warn-overwrite=yes --sysimage $$(call cygpath_w,$$<) $$(call cygpath_w,$$(JULIAHOME)/contrib/generate_precompile.jl) $(JULIA_PRECOMPILE); then \
 		echo '*** This error is usually fixed by running `make clean`. If the error persists$$(COMMA) try `make cleanall`. ***'; \
 		false; \
 	fi )