Bug#25611609 LINK WITH DYNAMIC RUNTIME LIBRARIES ON WINDOWS

Patch for 5.7 and up. Add option LINK_STATIC_RUNTIME_LIBRARIES, defalt OFF.

Author: Tor Didriksen

cmake/os/Windows.cmake

@@ -67,6 +67,7 @@ ENDIF()
 OPTION(WIN_DEBUG_NO_INLINE "Disable inlining for debug builds on Windows" OFF)
 
 IF(MSVC)
+  OPTION(LINK_STATIC_RUNTIME_LIBRARIES "Link with /MT" OFF)
   # Enable debug info also in Release build,
   # and create PDB to be able to analyze crashes.
   FOREACH(type EXE SHARED MODULE)
@@ -103,8 +104,9 @@ IF(MSVC)
      CMAKE_C_FLAGS_DEBUG      CMAKE_C_FLAGS_DEBUG_INIT 
      CMAKE_CXX_FLAGS_RELEASE  CMAKE_CXX_FLAGS_RELWITHDEBINFO
      CMAKE_CXX_FLAGS_DEBUG    CMAKE_CXX_FLAGS_DEBUG_INIT)
-#    Disable this substitution, use default, which is /MD
-#    STRING(REPLACE "/MD"  "/MT" "${flag}" "${${flag}}")
+     IF(LINK_STATIC_RUNTIME_LIBRARIES)
+       STRING(REPLACE "/MD"  "/MT" "${flag}" "${${flag}}")
+     ENDIF()
      STRING(REPLACE "/Zi"  "/Z7" "${flag}" "${${flag}}")
      IF (NOT WIN_DEBUG_NO_INLINE)
        STRING(REPLACE "/Ob0"  "/Ob1" "${flag}" "${${flag}}")