Restore depfile toleration of multiple output paths on distinct lines

Prior to introduction of depfile parser handling of multiple rules,
ninja silently accepted a depfile of the form:

    out: in1 in2 in3
    other: otherIn1 otherIn2 otherIn3

and incorrectly treated `other` and `otherIn*` as additional inputs to
`out`.  Now we prefer to reject this just as we already do for a depfile
specifying multiple outputs on one line.  However, this can break
existing cases where such a depfile was silently tolerated.

Add a `-w depfilemulti={err,warn}` option to control this behavior,
and make it just a warning by default.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/graph.cc b/src/graph.cc
index b41c247..9c2f784 100644
--- a/src/graph.cc
+++ b/src/graph.cc
@@ -491,7 +491,9 @@ bool ImplicitDepLoader::LoadDepFile(Edge* edge, const string& path,
     return false;
   }
 
-  DepfileParser depfile;
+  DepfileParser depfile(depfile_parser_options_
+                        ? *depfile_parser_options_
+                        : DepfileParserOptions());
   string depfile_err;
   if (!depfile.Parse(&content, &depfile_err)) {
     *err = path + ": " + depfile_err;