Merge pull request #5396 from hesmar/hesmar/fixCmakeInstallHeader Windows: install missing headers

diff --git a/cmake/extract_includes.bat.in b/cmake/extract_includes.bat.in
index 5cbd5f4..5ccce7f 100644
--- a/cmake/extract_includes.bat.in
+++ b/cmake/extract_includes.bat.in

@@ -99,6 +99,7 @@
 copy "${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\stubs\stl_util.h" include\google\protobuf\stubs\stl_util.h
 copy "${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\stubs\strutil.h" include\google\protobuf\stubs\strutil.h
 copy "${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\stubs\stringpiece.h" include\google\protobuf\stubs\stringpiece.h
+copy "${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\stubs\strutil.h" include\google\protobuf\stubs\strutil.h
 copy "${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\stubs\template_util.h" include\google\protobuf\stubs\template_util.h
 copy "${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\text_format.h" include\google\protobuf\text_format.h
 copy "${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\timestamp.pb.h" include\google\protobuf\timestamp.pb.h