Pass argc/argv/envp to dso constructors

The glibc implementation of the loader passes argc/argv/envp
to all elf constructors. This change makes bionic linker
behave in the same way.

Bug: http://b/30145768
Change-Id: I1c65c42aa5305a5b133c64b5748205bbde869e0e
Test: run bionic-unit-tests --gtest_filter=dl*:Dl*
diff --git a/linker/linker_logger.h b/linker/linker_logger.h
index 6b06aff..0932471 100644
--- a/linker/linker_logger.h
+++ b/linker/linker_logger.h
@@ -54,6 +54,6 @@
 };
 
 extern LinkerLogger g_linker_logger;
-extern const char* g_argv0;
+extern char** g_argv;
 
 #endif /* _LINKER_LOGGER_H_ */