Don't try to use -MMD / .o.d depfiles for ninja with .s files.

pylib/gyp/generator/ninja.py

Index: pylib/gyp/generator/ninja.py
diff --git a/pylib/gyp/generator/ninja.py b/pylib/gyp/generator/ninja.py
index 49be332365bc77a25299b3fedab18167212c4d18..177eec3f77be5ec5d88f94d2aa2b64c41ff26225 100644
--- a/pylib/gyp/generator/ninja.py
+++ b/pylib/gyp/generator/ninja.py
@@ -782,8 +782,10 @@ class NinjaWriter:
       obj_ext = self.obj_ext
       if ext in ('cc', 'cpp', 'cxx'):
         command = 'cxx'
-      elif ext == 'c' or (ext in ('s', 'S') and self.flavor != 'win'):
+      elif ext == 'c' or (ext == 'S' and self.flavor != 'win'):
         command = 'cc'
+      elif ext == 's' and self.flavor != 'win':  # Doesn't generate .o.d files.
+        command = 'cc_s'
       elif (self.flavor == 'win' and ext == 'asm' and
             self.msvs_settings.GetTargetPlatform(config_name) == 'Win32'):
         # Asm files only get auto assembled for x86 (not x64).
@@ -1431,6 +1433,11 @@ def GenerateOutputForConfig(target_list, target_dicts, data, params,
               '$cflags_pch_c -c $in -o $out'),
       depfile='$out.d')
     master_ninja.rule(
+      'cc_s',
+      description='CC $out',
+      command=('$cc $defines $includes $cflags $cflags_c '
+              '$cflags_pch_c -c $in -o $out'))
+    master_ninja.rule(
       'cxx',
       description='CXX $out',
       command=('$cxx -MMD -MF $out.d $defines $includes $cflags $cflags_cc '