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, 17 insertions, 0 deletions

diff --git a/src/depfile_parser.h b/src/depfile_parser.h
index 1e6ebb5..be20374 100644
--- a/src/depfile_parser.h
+++ b/src/depfile_parser.h
@@ -21,8 +21,24 @@ using namespace std;
 
 #include "string_piece.h"
 
+enum DepfileDistinctTargetLinesAction {
+  kDepfileDistinctTargetLinesActionWarn,
+  kDepfileDistinctTargetLinesActionError,
+};
+
+struct DepfileParserOptions {
+  DepfileParserOptions()
+      : depfile_distinct_target_lines_action_(
+          kDepfileDistinctTargetLinesActionWarn) {}
+  DepfileDistinctTargetLinesAction
+    depfile_distinct_target_lines_action_;
+};
+
 /// Parser for the dependency information emitted by gcc's -M flags.
 struct DepfileParser {
+  explicit DepfileParser(DepfileParserOptions options =
+                         DepfileParserOptions());
+
   /// Parse an input file.  Input must be NUL-terminated.
   /// Warning: may mutate the content in-place and parsed StringPieces are
   /// pointers within it.
@@ -30,6 +46,7 @@ struct DepfileParser {
 
   StringPiece out_;
   vector<StringPiece> ins_;
+  DepfileParserOptions options_;
 };
 
 #endif // NINJA_DEPFILE_PARSER_H_