Merge pull request #4848 from rescript-lang/fix_windows_file_error

fix "The process cannot access the file because it is being used by another process" on windows

Author: bobzhang

jscomp/bsb/bsb_ninja_gen.ml

@@ -108,7 +108,7 @@ let output_installation_file cwd_lib_bs namespace files_to_install =
   let bs = ".."//"bs" in  
   let sb = ".."//".." in 
   o (if Ext_sys.is_windows_or_cygwin then 
-      "rule cp\n  command = cmd.exe /C copy /Y $i $out > null\n"
+      "rule cp\n  command = cmd.exe /C copy /Y $i $out >NUL\n"
     else
       "rule cp\n  command = cp $i $out\n"
     );

jscomp/bsb/bsb_ninja_rule.ml

@@ -242,7 +242,7 @@ let make_custom_rules
     define 
       ~command:(
         if Ext_sys.is_windows_or_cygwin then
-          "cmd.exe /C copy /Y $i $out > null" 
+          "cmd.exe /C copy /Y $i $out >NUL" 
         else "cp $i $out"
       )
       "copy_resource" in

lib/4.06.1/bsb.ml

@@ -12998,7 +12998,7 @@ let make_custom_rules
     define 
       ~command:(
         if Ext_sys.is_windows_or_cygwin then
-          "cmd.exe /C copy /Y $i $out > null" 
+          "cmd.exe /C copy /Y $i $out >NUL" 
         else "cp $i $out"
       )
       "copy_resource" in
@@ -13616,7 +13616,7 @@ let output_installation_file cwd_lib_bs namespace files_to_install =
   let bs = ".."//"bs" in  
   let sb = ".."//".." in 
   o (if Ext_sys.is_windows_or_cygwin then 
-      "rule cp\n  command = cmd.exe /C copy /Y $i $out > null\n"
+      "rule cp\n  command = cmd.exe /C copy /Y $i $out >NUL\n"
     else
       "rule cp\n  command = cp $i $out\n"
     );