toolchain/53013: cross-compiling amd64 release on Darwin fails

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>Number:         53013
>Category:       toolchain
>Synopsis:       cross-compiling amd64 release on Darwin fails
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    toolchain-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Feb 12 15:00:01 +0000 2018
>Originator:     Sevan Janiyan
>Release:        NetBSD-HEAD
>Organization:
>Environment:
Darwin 17.4.0 x86_64 i386
>Description:
--- libstdc++.so.8.1 ---
#     build  libstdc++-v3/libstdc++.so.8.1
rm -f libstdc++.so.8.1
/sandbox/netbsd-src/obj/tooldir.Darwin-17.4.0-x86_64/bin/x86_64--netbsd-gcc  -shared -Wl,-soname,libstdc++.so.8 -Wl,--warn-shared-textrel -Wl,-Map=libstdc++.so.8.map   --sysroot=/sandbox/netbsd-src/obj/destdir.amd64 -Wl,-O1  -Wl,--gc-sections  -Wl,--version-script=libstdc++-symbols.ver -Wl,-z,relro -Wl,--warn-shared-textrel  -o libstdc++.so.8.1.tmp  -Wl,-rpath-link,/sandbox/netbsd-src/obj/destdir.amd64/lib  -L=/lib -Wl,-x  -Wl,--whole-archive libstdc++_pic.a  -Wl,--no-whole-archive -L/sandbox/netbsd-src/lib/libm/obj -lm 
/sandbox/netbsd-src/obj/tooldir.Darwin-17.4.0-x86_64/lib/gcc/x86_64--netbsd/6.4.0/../../../../x86_64--netbsd/bin/ld:libstdc++-symbols.ver:1: syntax error in VERSION script
collect2: error: ld returned 1 exit status

x86_64--netbsd-gcc is gcc version 6.4.0 (NetBSD nb1 20180203)
>How-To-Repeat:
run ./build.sh -U -m amd64 release on macOS high sierra
>Fix: