Attempt to fix setting MSVC runtime for sub-build.

Author: jonsimantov

cmake/external_rules.cmake

@@ -156,11 +156,19 @@ function(build_external_dependencies)
         set(SUBBUILD_MSVC_RUNTIME_FLAG "/MTd")
         set(CMAKE_SUB_CONFIGURE_OPTIONS
             ${CMAKE_SUB_CONFIGURE_OPTIONS}
+            -DCMAKE_C_FLAGS_RELEASE="/MT"
+            -DCMAKE_C_FLAGS_DEBUG="/MTd"
+            -DCMAKE_CXX_FLAGS_RELEASE="/MT"
+            -DCMAKE_CXX_FLAGS_DEBUG="/MTd"
             -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreadedDebug)
       else()
         set(SUBBUILD_MSVC_RUNTIME_FLAG "/MDd")
         set(CMAKE_SUB_CONFIGURE_OPTIONS
             ${CMAKE_SUB_CONFIGURE_OPTIONS}
+            -DCMAKE_C_FLAGS_RELEASE="/MD"
+            -DCMAKE_C_FLAGS_DEBUG="/MDd"
+            -DCMAKE_CXX_FLAGS_RELEASE="/MD"
+            -DCMAKE_CXX_FLAGS_DEBUG="/MDd"
             -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreadedDebugDLL)
       endif()
     else()
@@ -169,11 +177,19 @@ function(build_external_dependencies)
         set(SUBBUILD_MSVC_RUNTIME_FLAG "/MT")
         set(CMAKE_SUB_CONFIGURE_OPTIONS
             ${CMAKE_SUB_CONFIGURE_OPTIONS}
+            -DCMAKE_C_FLAGS_RELEASE="/MT"
+            -DCMAKE_C_FLAGS_DEBUG="/MTd"
+            -DCMAKE_CXX_FLAGS_RELEASE="/MT"
+            -DCMAKE_CXX_FLAGS_DEBUG="/MTd"
             -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreaded)
       else()
         set(SUBBUILD_MSVC_RUNTIME_FLAG "/MD")
         set(CMAKE_SUB_CONFIGURE_OPTIONS
-            ${CMAKE_SUB_CONFIGURE_OPTIONS}
+            ${CMAKE_SUB_CONFIGURE_OPTIONS} 
+            -DCMAKE_C_FLAGS_RELEASE="/MD"
+            -DCMAKE_C_FLAGS_DEBUG="/MDd"
+            -DCMAKE_CXX_FLAGS_RELEASE="/MD"
+            -DCMAKE_CXX_FLAGS_DEBUG="/MDd"
             -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreadedDLL)
       endif()
     endif()