add "call" under Windows upon generator call
diff --git a/extra/FindNanopb.cmake b/extra/FindNanopb.cmake
index 928c012..e6b5591 100644
--- a/extra/FindNanopb.cmake
+++ b/extra/FindNanopb.cmake
@@ -126,6 +126,10 @@
     return()
   endif()
   set(NANOPB_OPTIONS_DIRS)
+  
+  if(MSVC)
+    set(CUSTOM_COMMAND_PREFIX call)
+  endif()
 
   if(NANOPB_GENERATE_CPP_RELPATH)
 	  list(APPEND _nanopb_include_path "-I${NANOPB_GENERATE_CPP_RELPATH}")
@@ -190,7 +194,7 @@
       set(GENERATOR_CORE_PYTHON_SRC ${GENERATOR_CORE_PYTHON_SRC} ${output})
       add_custom_command(
         OUTPUT ${output}
-        COMMAND ${PROTOBUF_PROTOC_EXECUTABLE}
+        COMMAND ${CUSTOM_COMMAND_PREFIX} ${PROTOBUF_PROTOC_EXECUTABLE}
         ARGS -I${GENERATOR_PATH}/proto
           --python_out=${GENERATOR_CORE_DIR} ${ABS_FIL}
         DEPENDS ${ABS_FIL}
@@ -272,7 +276,7 @@
     add_custom_command(
       OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${FIL_PATH_REL}/${FIL_WE}.pb.c"
              "${CMAKE_CURRENT_BINARY_DIR}/${FIL_PATH_REL}/${FIL_WE}.pb.h"
-      COMMAND  ${PROTOBUF_PROTOC_EXECUTABLE}
+      COMMAND ${CUSTOM_COMMAND_PREFIX} ${PROTOBUF_PROTOC_EXECUTABLE}
       ARGS ${_nanopb_include_path} -I${GENERATOR_PATH}
            -I${GENERATOR_CORE_DIR} -I${CMAKE_CURRENT_BINARY_DIR}
            --plugin=protoc-gen-nanopb=${NANOPB_GENERATOR_PLUGIN}
@@ -291,6 +295,10 @@
   if(NOT DEFINED NANOPB_GENERATE_CPP_STANDALONE)
     set(NANOPB_GENERATE_CPP_STANDALONE TRUE)
   endif()
+  
+  if(MSVC)
+      unset(CUSTOM_COMMAND_PREFIX)
+  endif()
 
   if (NANOPB_GENERATE_CPP_STANDALONE)
     set(${SRCS} ${${SRCS}} ${NANOPB_SRCS} PARENT_SCOPE)