Replace ErrorHandler with Errors and FormatErrors*

`ErrorHandler` complicated all error handling in wabt, since it was
callback-based. Callbacks would be useful if we ever wanted to change
behavior when an error occurred, but instead all that the handler ever
did was write the errors to stdout/stderr or to a buffer.

This change adds a new class `Error`, which contains an `ErrorLevel`, a
`Location` and an error message. It also replaces ErrorHandler with
`Errors` (a typedef for `std::vector<Error>`), and adds a couple of
functions that can format a list of `Errors` for output:
`FormatErrorsTo{String,File}`.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/lexer-source-line-finder.cc b/src/lexer-source-line-finder.cc
index 0936afa4..833cb900 100644
--- a/src/lexer-source-line-finder.cc
+++ b/src/lexer-source-line-finder.cc
@@ -28,6 +28,7 @@ LexerSourceLineFinder::LexerSourceLineFinder(
       next_line_start_(0),
       last_cr_(false),
       eof_(false) {
+  source_->Seek(0);
   // Line 0 should not be used; but it makes indexing simpler.
   line_ranges_.emplace_back(0, 0);
 }