win: Stop relying on %INCLUDE% for the resource compiler.

Instead, use -imsvc and the hermetic toolchain for the preprocessor, and
don't look in system include dirs for resources.

This means we can't include resources from the system include dirs,
but we don't want to do that anyways.

For now, keep using tool_wrapper to set the env so that we can
find MS rc.exe on %PATH%.

Bug: none
Change-Id: I1065be2513659c6eb5b4de440299fa86cfb58736
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1863149Reviewed-by: Hans Wennborg <hans@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#706916}

build/toolchain/win/BUILD.gn

@@ -212,7 +212,7 @@ template("msvc_toolchain") {
     }
 
     tool("rc") {
-      command = "$python_path $tool_wrapper_path rc-wrapper $env rc.exe /nologo {{defines}} {{include_dirs}} /fo{{output}} {{source}}"
+      command = "$python_path $tool_wrapper_path rc-wrapper $env rc.exe /nologo $sys_include_flags{{defines}} {{include_dirs}} /fo{{output}} {{source}}"
       depsformat = "msvc"
       outputs = [
         "$object_subdir/{{source_name_part}}.res",

build/toolchain/win/rc/rc.py

@@ -8,7 +8,8 @@ A resource compiler for .rc files.
 
 options:
 -h, --help     Print this message.
--I<dir>        Add include path.
+-I<dir>        Add include path, used for both headers and resources.
+-imsvc<dir>    Add system include path, used for preprocessing only.
 -D<sym>        Define a macro for the preprocessor.
 /fo<out>       Set path of output .res file.
 /nologo        Ignored (rc.py doesn't print a logo by default).
@@ -33,6 +34,7 @@ def ParseFlags():
   """Parses flags off sys.argv and returns the parsed flags."""
   # Can't use optparse / argparse because of /fo flag :-/
   includes = []
+  imsvcs = []
   defines = []
   output = None
   input = None
@@ -44,6 +46,8 @@ def ParseFlags():
       sys.exit(0)
     if flag.startswith('-I'):
       includes.append(flag)
+    elif flag.startswith('-imsvc'):
+      imsvcs.append(flag)
     elif flag.startswith('-D'):
       defines.append(flag)
     elif flag.startswith('/fo'):
@@ -72,10 +76,10 @@ def ParseFlags():
     sys.exit(1)
   if not output:
     output = os.path.splitext(input)[0] + '.res'
-  Flags = namedtuple('Flags', ['includes', 'defines', 'output', 'input',
-                               'show_includes'])
-  return Flags(includes=includes, defines=defines, output=output, input=input,
-               show_includes=show_includes)
+  Flags = namedtuple('Flags', ['includes', 'defines', 'output', 'imsvcs',
+                               'input', 'show_includes'])
+  return Flags(includes=includes, defines=defines, output=output, imsvcs=imsvcs,
+               input=input, show_includes=show_includes)
 
 
 def ReadInput(input):
@@ -119,13 +123,13 @@ def Preprocess(rc_file_data, flags):
   # Closing temp_handle immediately defeats the purpose of mkstemp(), but I
   # can't figure out how to let write to the temp file on Windows otherwise.
   os.close(temp_handle)
-  clang_cmd = [clang, '/P', '/DRC_INVOKED', '/TC', '-', '/Fi' + temp_file]
+  clang_cmd = [clang, '/P', '/X', '/DRC_INVOKED', '/TC', '-', '/Fi' + temp_file]
   if os.path.dirname(flags.input):
     # This must precede flags.includes.
     clang_cmd.append('-I' + os.path.dirname(flags.input))
   if flags.show_includes:
     clang_cmd.append('/showIncludes')
-  clang_cmd += flags.includes + flags.defines
+  clang_cmd += flags.imsvcs + flags.includes + flags.defines
   p = subprocess.Popen(clang_cmd, stdin=subprocess.PIPE)
   p.communicate(input=rc_file_data)
   if p.returncode != 0:
@@ -198,7 +202,7 @@ def CompareToMsRcOutput(preprocessed_output, is_utf8, flags):
     f.write(preprocessed_output)
 
   msrc_out = flags.output + '_ms_rc'
-  msrc_cmd = ['rc', '/nologo', '/fo' + msrc_out]
+  msrc_cmd = ['rc', '/nologo', '/x', '/fo' + msrc_out]
 
   # Make sure rc-relative resources can be found. rc.exe looks for external
   # resource files next to the file, but the preprocessed file isn't where the