hg: jdk/sandbox: 8205197: Never default to using libc++ on Linux

[chris.hegarty at oracle.com]

Changeset: a1d7444076e4
Author:    martin
Date:      2018-06-22 17:36 -0700
URL:       http://hg.openjdk.java.net/jdk/sandbox/rev/a1d7444076e4

8205197: Never default to using libc++ on Linux
Summary: Let the toolchain choose the standard library by default
Reviewed-by: tbell, erikj, gziemski

! make/autoconf/flags-ldflags.m4