8020799: Allow customization of hotspot source directories and files

Reviewed-by: kvn, dlong

make/linux/makefiles/vm.make

@@ -212,6 +212,12 @@ ifeq ($(Platform_arch_model), x86_64)
 Src_Files_EXCLUDE += \*x86_32\*
 endif
 
+# Alternate vm.make
+# This has to be included here to allow changes to the source
+# directories and excluded files before they are expanded
+# by the definition of Src_Files.
+-include $(HS_ALT_MAKE)/$(Platform_os_family)/makefiles/vm.make
+
 # Locate all source files in the given directory, excluding files in Src_Files_EXCLUDE.
 define findsrc
 	$(notdir $(shell find $(1)/. ! -name . -prune \
@@ -381,4 +387,4 @@ build: $(LIBJVM) $(LAUNCHER) $(LIBJSIG) $(LIBJVM_DB) $(BUILDLIBSAPROC) dtraceChe
 
 install: install_jvm install_jsig install_saproc
 
-.PHONY: default build install install_jvm $(HS_ALT_MAKE)/$(Platform_os_family)/makefiles/$(BUILDARCH).make
+.PHONY: default build install install_jvm $(HS_ALT_MAKE)/$(Platform_os_family)/makefiles/$(BUILDARCH).make $(HS_ALT_MAKE)/$(Platform_os_family)/makefiles/vm.make