--- a/make/CreateJmods.gmk	Wed May 09 17:14:29 2018 +0200
+++ b/make/CreateJmods.gmk	Wed May 09 19:50:30 2018 +0200
@@ -121,11 +121,21 @@
   ifeq ($(OPENJDK_TARGET_OS), windows)
     # Only java.base needs to include the MSVC*_DLLs. Make sure no other module
     # tries to include them (typically imported ones).
-    ifneq ($(wildcard $(LIBS_DIR)/$(notdir $(MSVCR_DLL))), )
-      JMOD_FLAGS += --exclude '$(notdir $(MSVCR_DLL))'
+    ifneq ($(MSVCR_DLL), )
+      ifneq ($(wildcard $(LIBS_DIR)/$(notdir $(MSVCR_DLL))), )
+        JMOD_FLAGS += --exclude '$(notdir $(MSVCR_DLL))'
+      endif
     endif
-    ifneq ($(wildcard $(LIBS_DIR)/$(notdir $(MSVCP_DLL))), )
-      JMOD_FLAGS += --exclude '$(notdir $(MSVCP_DLL))'
+    ifneq ($(MSVCP_DLL), )
+      ifneq ($(wildcard $(LIBS_DIR)/$(notdir $(MSVCP_DLL))), )
+        JMOD_FLAGS += --exclude '$(notdir $(MSVCP_DLL))'
+      endif
+    endif
+    ifneq ($(UCRT_DLL_DIR), )
+      UCRT_DLL_FILES := $(notdir $(wildcard $(UCRT_DLL_DIR)/*.dll))
+      ifneq ($(wildcard $(LIBS_DIR)/$(firstword $(UCRT_DLL_FILES))), )
+        JMOD_FLAGS += $(patsubst %, --exclude '%', $(UCRT_DLL_FILES))
+      endif
     endif
   endif
 endif

--- a/make/autoconf/basics.m4	Wed May 09 17:14:29 2018 +0200
+++ b/make/autoconf/basics.m4	Wed May 09 19:50:30 2018 +0200
@@ -671,6 +671,8 @@
       BASIC_EVAL_DEVKIT_VARIABLE([DEVKIT_MSVCR_DLL])
       # Corresponds to --with-msvcp-dll
       BASIC_EVAL_DEVKIT_VARIABLE([DEVKIT_MSVCP_DLL])
+      # Corresponds to --with-ucrt-dll-dir
+      BASIC_EVAL_DEVKIT_VARIABLE([DEVKIT_UCRT_DLL_DIR])
     fi
 
     AC_MSG_CHECKING([for devkit])

--- a/make/autoconf/spec.gmk.in	Wed May 09 17:14:29 2018 +0200
+++ b/make/autoconf/spec.gmk.in	Wed May 09 19:50:30 2018 +0200
@@ -736,6 +736,7 @@
 LIBZIP_CAN_USE_MMAP:=@LIBZIP_CAN_USE_MMAP@
 MSVCR_DLL:=@MSVCR_DLL@
 MSVCP_DLL:=@MSVCP_DLL@
+UCRT_DLL_DIR:=@UCRT_DLL_DIR@
 STLPORT_LIB:=@STLPORT_LIB@
 
 ####################################################

--- a/make/autoconf/toolchain_windows.m4	Wed May 09 17:14:29 2018 +0200
+++ b/make/autoconf/toolchain_windows.m4	Wed May 09 19:50:30 2018 +0200
@@ -76,6 +76,7 @@
 VS_MSVCR_2017=vcruntime140.dll
 VS_MSVCP_2017=msvcp140.dll
 VS_ENVVAR_2017="VS150COMNTOOLS"
+VS_USE_UCRT_2017="true"
 VS_VS_INSTALLDIR_2017="Microsoft Visual Studio/2017"
 VS_EDITIONS_2017="BuildTools Community Professional Enterprise"
 VS_SDK_INSTALLDIR_2017=
@@ -264,6 +265,7 @@
     eval VS_VERSION_INTERNAL="\${VS_VERSION_INTERNAL_${VS_VERSION}}"
     eval MSVCR_NAME="\${VS_MSVCR_${VS_VERSION}}"
     eval MSVCP_NAME="\${VS_MSVCP_${VS_VERSION}}"
+    eval USE_UCRT="\${VS_USE_UCRT_${VS_VERSION}}"
     eval PLATFORM_TOOLSET="\${VS_VS_PLATFORM_NAME_${VS_VERSION}}"
     VS_PATH="$TOOLCHAIN_PATH:$PATH"
 
@@ -309,6 +311,7 @@
       eval VS_VERSION_INTERNAL="\${VS_VERSION_INTERNAL_${VS_VERSION}}"
       eval MSVCR_NAME="\${VS_MSVCR_${VS_VERSION}}"
       eval MSVCP_NAME="\${VS_MSVCP_${VS_VERSION}}"
+      eval USE_UCRT="\${VS_USE_UCRT_${VS_VERSION}}"
       # The rest of the variables are already evaled while probing
       AC_MSG_NOTICE([Found $VS_DESCRIPTION])
       break
@@ -432,8 +435,11 @@
       VS_INCLUDE=`$ECHO "$VS_INCLUDE" | $SED -e 's/\\\\*;* *$//'`
       VS_LIB=`$ECHO "$VS_LIB" | $SED 's/\\\\*;* *$//'`
       VCINSTALLDIR=`$ECHO "$VCINSTALLDIR" | $SED 's/\\\\* *$//'`
-      WindowsSDKDir=`$ECHO "$WindowsSDKDir" | $SED 's/\\\\* *$//'`
+      WindowsSdkDir=`$ECHO "$WindowsSdkDir" | $SED 's/\\\\* *$//'`
       WINDOWSSDKDIR=`$ECHO "$WINDOWSSDKDIR" | $SED 's/\\\\* *$//'`
+      if test -z "$WINDOWSSDKDIR"; then
+        WINDOWSSDKDIR="$WindowsSdkDir"
+      fi
       # Remove any paths containing # (typically F#) as that messes up make. This
       # is needed if visual studio was installed with F# support.
       VS_PATH=`$ECHO "$VS_PATH" | $SED 's/[[^:#]]*#[^:]*://g'`
@@ -539,7 +545,7 @@
   if test "x$MSVC_DLL" = x; then
     if test "x$VCINSTALLDIR" != x; then
       CYGWIN_VC_INSTALL_DIR="$VCINSTALLDIR"
-      BASIC_WINDOWS_REWRITE_AS_UNIX_PATH(CYGWIN_VC_INSTALL_DIR)
+      BASIC_FIXUP_PATH(CYGWIN_VC_INSTALL_DIR)
       if test "$VS_VERSION" -lt 2017; then
         # Probe: Using well-known location from Visual Studio 12.0 and older
         if test "x$OPENJDK_TARGET_CPU_BITS" = x64; then
@@ -673,4 +679,41 @@
     fi
     AC_SUBST(MSVCP_DLL)
   fi
+
+  AC_ARG_WITH(ucrt-dll-dir, [AS_HELP_STRING([--with-ucrt-dll-dir],
+      [path to Microsoft Windows Kit UCRT DLL dir (Windows only) @<:@probed@:>@])])
+
+  if test "x$USE_UCRT" = "xtrue"; then
+    AC_MSG_CHECKING([for UCRT DLL dir])
+    if test "x$with_ucrt_dll_dir" != x; then
+      if test -z "$(ls -d "$with_ucrt_dll_dir/*.dll" 2> /dev/null)"; then
+        AC_MSG_RESULT([no])
+        AC_MSG_ERROR([Could not find any dlls in $with_ucrt_dll_dir])
+      else
+        AC_MSG_RESULT([$with_ucrt_dll_dir])
+        UCRT_DLL_DIR="$with_ucrt_dll_dir"
+        BASIC_FIXUP_PATH([UCRT_DLL_DIR])
+      fi
+    elif test "x$DEVKIT_UCRT_DLL_DIR" != "x"; then
+      UCRT_DLL_DIR="$DEVKIT_UCRT_DLL_DIR"
+      AC_MSG_RESULT($UCRT_DLL_DIR)
+    else
+      CYGWIN_WINDOWSSDKDIR="${WINDOWSSDKDIR}"
+      BASIC_FIXUP_PATH([CYGWIN_WINDOWSSDKDIR])
+      dll_subdir=$OPENJDK_TARGET_CPU
+      if test "x$dll_subdir" = "xx86_64"; then
+        dll_subdir="x64"
+      fi
+      UCRT_DLL_DIR="$CYGWIN_WINDOWSSDKDIR/Redist/ucrt/DLLs/$dll_subdir"
+      if test -z "$(ls -d "$UCRT_DLL_DIR/"*.dll 2> /dev/null)"; then
+        AC_MSG_RESULT([no])
+        AC_MSG_ERROR([Could not find any dlls in $UCRT_DLL_DIR])
+      else
+        AC_MSG_RESULT($UCRT_DLL_DIR)
+      fi
+    fi
+  else
+    UCRT_DLL_DIR=
+  fi
+  AC_SUBST(UCRT_DLL_DIR)
 ])

--- a/make/copy/Copy-java.base.gmk	Wed May 09 17:14:29 2018 +0200
+++ b/make/copy/Copy-java.base.gmk	Wed May 09 19:50:30 2018 +0200
@@ -65,6 +65,17 @@
       MACRO := copy-and-chmod))
 
   TARGETS += $(COPY_MSVCR) $(COPY_MSVCP)
+
+  ifneq ($(UCRT_DLL_DIR), )
+    $(eval $(call SetupCopyFiles, COPY_UCRT_DLLS, \
+        DEST := $(LIB_DST_DIR), \
+        SRC := $(UCRT_DLL_DIR), \
+        FILES := $(wildcard $(UCRT_DLL_DIR)/*.dll), \
+        MACRO := copy-and-chmod, \
+    ))
+
+    TARGETS += $(COPY_UCRT_DLLS)
+  endif
 endif
 
 ################################################################################

--- a/make/devkit/createWindowsDevkit2017.sh	Wed May 09 17:14:29 2018 +0200
+++ b/make/devkit/createWindowsDevkit2017.sh	Wed May 09 19:50:30 2018 +0200
@@ -130,6 +130,8 @@
     cp -r "$SDK_INSTALL_DIR/lib/$SDK_FULL_VERSION/um/x86" $DEVKIT_ROOT/$SDK_VERSION/lib/
     cp -r "$SDK_INSTALL_DIR/lib/$SDK_FULL_VERSION/ucrt/x64" $DEVKIT_ROOT/$SDK_VERSION/lib/
     cp -r "$SDK_INSTALL_DIR/lib/$SDK_FULL_VERSION/ucrt/x86" $DEVKIT_ROOT/$SDK_VERSION/lib/
+    mkdir -p $DEVKIT_ROOT/$SDK_VERSION/Redist
+    cp -r "$SDK_INSTALL_DIR/Redist/ucrt" $DEVKIT_ROOT/$SDK_VERSION/Redist/
     mkdir -p $DEVKIT_ROOT/$SDK_VERSION/include
     cp -r "$SDK_INSTALL_DIR/include/$SDK_FULL_VERSION/"* $DEVKIT_ROOT/$SDK_VERSION/include/
 fi
@@ -152,12 +154,14 @@
 echo-info "DEVKIT_VS_LIB_x86=\"\$DEVKIT_ROOT/VC/lib/x86;\$DEVKIT_ROOT/VC/atlmfc/lib/x86;\$DEVKIT_ROOT/$SDK_VERSION/lib/x86\""
 echo-info "DEVKIT_MSVCR_DLL_x86=\"\$DEVKIT_ROOT/VC/redist/x86/$MSVCR_DLL\""
 echo-info "DEVKIT_MSVCP_DLL_x86=\"\$DEVKIT_ROOT/VC/redist/x86/$MSVCP_DLL\""
+echo-info "DEVKIT_UCRT_DLL_DIR_x86=\"\$DEVKIT_ROOT/10/Redist/ucrt/DLLs/x86\""
 echo-info ""
 echo-info "DEVKIT_TOOLCHAIN_PATH_x86_64=\"\$DEVKIT_ROOT/VC/bin/x64:\$DEVKIT_ROOT/$SDK_VERSION/bin/x64:\$DEVKIT_ROOT/$SDK_VERSION/bin/x86\""
 echo-info "DEVKIT_VS_INCLUDE_x86_64=\"\$DEVKIT_ROOT/VC/include;\$DEVKIT_ROOT/VC/atlmfc/include;\$DEVKIT_ROOT/$SDK_VERSION/include/shared;\$DEVKIT_ROOT/$SDK_VERSION/include/ucrt;\$DEVKIT_ROOT/$SDK_VERSION/include/um;\$DEVKIT_ROOT/$SDK_VERSION/include/winrt\""
 echo-info "DEVKIT_VS_LIB_x86_64=\"\$DEVKIT_ROOT/VC/lib/x64;\$DEVKIT_ROOT/VC/atlmfc/lib/x64;\$DEVKIT_ROOT/$SDK_VERSION/lib/x64\""
 echo-info "DEVKIT_MSVCR_DLL_x86_64=\"\$DEVKIT_ROOT/VC/redist/x64/$MSVCR_DLL\""
 echo-info "DEVKIT_MSVCP_DLL_x86_64=\"\$DEVKIT_ROOT/VC/redist/x64/$MSVCP_DLL\""
+echo-info "DEVKIT_UCRT_DLL_DIR_x86_64=\"\$DEVKIT_ROOT/10/Redist/ucrt/DLLs/x64\""
 
 ################################################################################
 # Copy this script