[build] Port "Add patched eu-strip in third_party"

This ports:
https://chromium-review.googlesource.com/c/544798/

This is needed to unblock rolling build into v8 at:
https://chromium-review.googlesource.com/c/v8/v8/+/657634

Bug: chromium:593874, chromium:742655
Change-Id: Ie00f2d13cfd052881a84b6e0cb95c336b7d2581c
Reviewed-on: https://chromium-review.googlesource.com/680815
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48134}

.gitignore

@@ -64,6 +64,7 @@
 /testing/gtest
 /third_party/*
 !/third_party/binutils
+!/third_party/eu-strip
 !/third_party/inspector_protocol
 /tools/clang
 /tools/gcmole/gcmole-tools

third_party/eu-strip/README.v8

+Name: eu-strip
+URL: https://sourceware.org/elfutils/
+Version: 0.158
+Security Critical: no
+License: LGPL 3
+License File: NOT_SHIPPED
+
+Description:
+
+Patched eu-strip from elfutils.
+
+Build instructions (on Trusty; note that this will build the
+Ubuntu-patched version of elfutils):
+$ mkdir elfutils
+$ cd elfutils
+$ apt-get source elfutils
+$ cd elfutils-0.158
+[ Edit libelf/elf_end.c and remove the free() on line 164. ]
+$ ./configure
+$ make
+$ gcc -std=gnu99 -Wall -Wshadow -Wunused -Wextra -fgnu89-inline
+  -Wformat=2 -Werror -g -O2 -Wl,-rpath-link,libelf:libdw -o eu-strip
+  src/strip.o libebl/libebl.a libelf/libelf.a lib/libeu.a -ldl
+$ eu-strip ./eu-strip  # Keep the binary small, please.