Merge pull request #10270 from jtattermusch/csharp_static_runtime

Link grpc_csharp_ext with static runtime.

cmake/msvc_static_runtime.cmake

@@ -3,6 +3,8 @@ option(gRPC_MSVC_STATIC_RUNTIME "Link with static msvc runtime libraries" OFF)
 if(gRPC_MSVC_STATIC_RUNTIME)
   # switch from dynamic to static linking of msvcrt
   foreach(flag_var
+    CMAKE_C_FLAGS CMAKE_C_FLAGS_DEBUG CMAKE_C_FLAGS_RELEASE
+    CMAKE_C_FLAGS_MINSIZEREL CMAKE_C_FLAGS_RELWITHDEBINFO
     CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
     CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
 

tools/run_tests/helper_scripts/pre_build_csharp.bat

@@ -43,7 +43,7 @@ cd build
 mkdir %ARCHITECTURE%
 cd %ARCHITECTURE%
 @rem TODO(jtattermusch): Stop hardcoding path to yasm once Jenkins workers can locate yasm correctly
-cmake -G "Visual Studio 14 2015" -A %ARCHITECTURE% -DgRPC_BUILD_TESTS=OFF -DCMAKE_ASM_NASM_COMPILER="C:/Program Files (x86)/yasm/yasm.exe" ../../.. || goto :error
+cmake -G "Visual Studio 14 2015" -A %ARCHITECTURE% -DgRPC_BUILD_TESTS=OFF -DgRPC_MSVC_STATIC_RUNTIME=ON -DCMAKE_ASM_NASM_COMPILER="C:/Program Files (x86)/yasm/yasm.exe" ../../.. || goto :error
 cd ..\..\..
 
 @rem Location of nuget.exe