--- old/make/common/JdkNativeCompilation.gmk	2018-06-08 10:48:30.719893666 +0200
+++ new/make/common/JdkNativeCompilation.gmk	2018-06-08 10:48:30.431893668 +0200
@@ -32,6 +32,36 @@
 
 include NativeCompilation.gmk
 
+# Hook to include the corresponding custom file, if present.
+$(eval $(call IncludeCustomExtension, common/JdkNativeCompilation.gmk))
+
+FindSrcDirsForLib += \
+  $(call uniq, $(wildcard \
+      $(TOPDIR)/src/$(strip $1)/$(OPENJDK_TARGET_OS)/native/lib$(strip $2) \
+      $(TOPDIR)/src/$(strip $1)/$(OPENJDK_TARGET_OS_TYPE)/native/lib$(strip $2) \
+      $(TOPDIR)/src/$(strip $1)/share/native/lib$(strip $2)))
+
+FindSrcDirsForComponent += \
+  $(call uniq, $(wildcard \
+      $(TOPDIR)/src/$(strip $1)/$(OPENJDK_TARGET_OS)/native/$(strip $2) \
+      $(TOPDIR)/src/$(strip $1)/$(OPENJDK_TARGET_OS_TYPE)/native/$(strip $2) \
+      $(TOPDIR)/src/$(strip $1)/share/native/$(strip $2)))
+
+GetJavaHeaderDir = \
+  $(wildcard $(SUPPORT_OUTPUTDIR)/headers/$(strip $1))
+
+# Process a dir description such as "java.base:headers" into a set of proper absolute paths.
+ProcessDir = \
+  $(if $(findstring :, $1), \
+    $(call FindSrcDirsForComponent, $(firstword $(subst :, , $1)), $(lastword $(subst :, , $1))) \
+  , \
+    $(if $(filter /%, $1), \
+      $1 \
+    , \
+      $(call FindSrcDirsForComponent, $(MODULE), $1) \
+    ) \
+  )
+
 # Setup make rules for creating a native shared library with suitable defaults
 # for the OpenJDK project.
 #
@@ -39,8 +69,16 @@
 # and the targets generated are listed in a variable by that name.
 #
 # Remaining parameters are named arguments. These are all passed on to
-# SetupNativeCompilation, except for 
+# SetupNativeCompilation, except for
 #   EXTRA_RC_FLAGS -- additional RC_FLAGS to append.
+#   EXTRA_HEADER_DIRS -- additional directories to look for headers in
+#   EXTRA_SRC -- additional directories to look for source in
+#   EXCLUDE_SRC_PATTERNS -- exclude source dirs matching these patterns from
+#     appearing in SRC.
+#   HEADERS_FROM_SRC -- if false, does not add source dirs automatically as
+#     header include dirs. (Defaults to true.)
+#   SRC -- this is passed on, but preprocessed to accept source dir designations
+#     such as "java.base:headers".
 SetupJdkLibrary = $(NamedParamsMacroTemplate)
 define SetupJdkLibraryBody
   ifeq ($$($1_OUTPUT_DIR), )
@@ -51,6 +89,20 @@
     $1_OBJECT_DIR := $$(SUPPORT_OUTPUTDIR)/native/$$(MODULE)/lib$$($1_NAME)
   endif
 
+  ifeq ($$($1_SRC), )
+    $1_SRC := $$(call FindSrcDirsForLib, $$(MODULE), $$($1_NAME))
+  else
+    $1_SRC := $$(foreach dir, $$($1_SRC), $$(call ProcessDir, $$(dir)))
+  endif
+  ifneq ($$($1_EXTRA_SRC), )
+    $1_SRC += $$(foreach dir, $$($1_EXTRA_SRC), $$(call ProcessDir, $$(dir)))
+  endif
+
+  ifneq ($$($1_EXCLUDE_SRC_PATTERNS), )
+    $1_EXCLUDE_SRC := $$(call containing, $$($1_EXCLUDE_SRC_PATTERNS), $$($1_SRC))
+    $1_SRC := $$(filter-out $$($1_EXCLUDE_SRC), $$($1_SRC))
+  endif
+
   ifeq ($$($1_VERSIONINFO_RESOURCE), )
     $1_VERSIONINFO_RESOURCE := $$(GLOBAL_VERSION_INFO_RESOURCE)
   else ifeq ($$($1_VERSIONINFO_RESOURCE), DISABLE)
@@ -66,6 +118,25 @@
     $1_RC_FLAGS :=
   endif
 
+  ifneq ($$($1_HEADERS_FROM_SRC), false)
+    $1_SRC_HEADER_FLAGS := $$(foreach dir, $$(wildcard $$($1_SRC) \
+        $$(call GetJavaHeaderDir, $$(MODULE))), -I$$(dir))
+  endif
+  ifneq ($$($1_EXTRA_HEADER_DIRS), )
+    $1_PROCESSED_EXTRA_HEADER_DIRS := $$(foreach dir, $$($1_EXTRA_HEADER_DIRS), \
+        $$(call ProcessDir, $$(dir)))
+    $1_EXTRA_HEADER_FLAGS := $$(addprefix -I, $$($1_PROCESSED_EXTRA_HEADER_DIRS))
+  endif
+
+  ifneq ($$($1_CFLAGS), )
+    $1_CFLAGS += $$($1_SRC_HEADER_FLAGS) $$($1_EXTRA_HEADER_FLAGS)
+  endif
+  ifneq ($$($1_CXXFLAGS), )
+    $1_CXXFLAGS += $$($1_SRC_HEADER_FLAGS) $$($1_EXTRA_HEADER_FLAGS)
+  endif
+  ifeq ($$($1_CFLAGS)$$($1_CXXFLAGS), )
+    $1_CFLAGS += $$($1_SRC_HEADER_FLAGS) $$($1_EXTRA_HEADER_FLAGS)
+  endif
   $1_RC_FLAGS += $$($1_EXTRA_RC_FLAGS)
 
   # Since we reuse the rule name ($1), all our arguments will pass through.
@@ -80,7 +151,7 @@
 # and the targets generated are listed in a variable by that name.
 #
 # Remaining parameters are named arguments. These are all passed on to
-# SetupNativeCompilation, except for 
+# SetupNativeCompilation, except for
 #   EXTRA_RC_FLAGS -- additional RC_FLAGS to append.
 SetupJdkExecutable = $(NamedParamsMacroTemplate)
 define SetupJdkExecutableBody