Relocate DWARF using .oat_patches.

The current solution is to hard-code knowledge of DWARF in the linker.
This works for simple use of DWARF, but breaks as soon as I try to do
anything more complex.  Making the linker fully support DWARF would be
non-trivial task and would be essentially rewrite.  Using .oat_patches
is much easier solution.

Relocating .debug_* sections required extending .oat_patches to support
more sections than just .text.  I have encoded each section as
null-terminated section name followed by ULEB128 deltas.

The ULEB128 encoding shrinks .oat_patches for .text by factor of
about 6 with 64-bit compiler, and factor of 3 with 32-bit compiler.

On the other hand, it grows by the extra .oat_patches for DWARF which
were not present before (if debug symbols are included).

Overall, it is still a clear improvement even with the DWARF patches.

Change-Id: I78ffeda0f8a3da03341995a3b5ef15c954e16e9f
diff --git a/compiler/elf_writer_quick.h b/compiler/elf_writer_quick.h
index 4990ed0..811beb4 100644
--- a/compiler/elf_writer_quick.h
+++ b/compiler/elf_writer_quick.h
@@ -19,6 +19,7 @@
 
 #include "elf_utils.h"
 #include "elf_writer.h"
+#include "oat_writer.h"
 
 namespace art {
 
@@ -36,6 +37,9 @@
                      const CompilerDriver& driver)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
+  static void EncodeOatPatches(const OatWriter::PatchLocationsMap& sections,
+                               std::vector<uint8_t>* buffer);
+
  protected:
   bool Write(OatWriter* oat_writer,
              const std::vector<const DexFile*>& dex_files,