Change the MSVC static runtime CMake option name and moved it into the library directory

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5b4cd40..f31794d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -242,18 +242,6 @@
     endif(CMAKE_COMPILER_IS_CLANG OR CMAKE_COMPILER_IS_GNU)
 endif(MBEDTLS_FATAL_WARNINGS)
 
-if(MSVC)
-    option(BUILD_WITH_STATIC_RUNTIME "Build the libraries with /MT compiler flag" OFF)
-    if(BUILD_WITH_STATIC_RUNTIME)
-        foreach(flag_var
-            CMAKE_C_FLAGS CMAKE_C_FLAGS_DEBUG CMAKE_C_FLAGS_RELEASE
-            CMAKE_C_FLAGS_MINSIZEREL CMAKE_C_FLAGS_RELWITHDEBINFO
-            CMAKE_C_FLAGS_CHECK)
-            string(REGEX REPLACE "/MD" "/MT" ${flag_var} "${${flag_var}}")
-        endforeach(flag_var)
-    endif()
-endif()
-
 if(CMAKE_BUILD_TYPE STREQUAL "Coverage")
     if(CMAKE_COMPILER_IS_GNU OR CMAKE_COMPILER_IS_CLANG)
         set(CMAKE_SHARED_LINKER_FLAGS "--coverage")
diff --git a/library/CMakeLists.txt b/library/CMakeLists.txt
index df7f170..f07d3b4 100644
--- a/library/CMakeLists.txt
+++ b/library/CMakeLists.txt
@@ -187,6 +187,18 @@
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wmissing-declarations -Wmissing-prototypes -Wdocumentation -Wno-documentation-deprecated-sync -Wunreachable-code")
 endif(CMAKE_COMPILER_IS_CLANG)
 
+if(CMAKE_COMPILER_IS_MSVC)
+    option(MSVC_STATIC_RUNTIME "Build the libraries with /MT compiler flag" OFF)
+    if(MSVC_STATIC_RUNTIME)
+        foreach(flag_var
+            CMAKE_C_FLAGS CMAKE_C_FLAGS_DEBUG CMAKE_C_FLAGS_RELEASE
+            CMAKE_C_FLAGS_MINSIZEREL CMAKE_C_FLAGS_RELWITHDEBINFO
+            CMAKE_C_FLAGS_CHECK)
+            string(REGEX REPLACE "/MD" "/MT" ${flag_var} "${${flag_var}}")
+        endforeach(flag_var)
+    endif()
+endif()
+
 if(WIN32)
     set(libs ${libs} ws2_32)
 endif(WIN32)