Remove yet more fixed-length buffers (and their overruns).

Bug: 20317724
Change-Id: If137fc96f5f23576ccecd388ac87afefa47337c6
diff --git a/adb_utils.h b/adb_utils.h
index ec8e8b5..4b64afa 100644
--- a/adb_utils.h
+++ b/adb_utils.h
@@ -19,6 +19,7 @@
 
 #include <string>
 
+bool getcwd(std::string* cwd);
 bool directory_exists(const std::string& path);
 
 std::string escape_arg(const std::string& s);