RFR: JDK-8167479: arm 32/64 slowdebug fails to build on unpack200

[Erik Joelsson]

Hello,

After the cleanup of C++ linking with the GCC toolchain. We missed 
updating one instance with the correct TOOLCHAIN configuration. This 
leads to build failures for arm ports with slowdebug. I have no idea why 
it only happens there, but correcting the TOOLCHAIN configuration (so 
that g++ is used to link instead of gcc) makes it build again.

The build error looks like this:

/localhome/hg/jdk9-dev-CDR/build/linux-arm64-slowdebug/support/native/jdk.pack200/unpackexe/bands.o:(.data.DW.ref.__gxx_personality_v0[DW.ref.__gxx_personality_v0]+0x0): 
undefined reference to `__gxx_personality_v0'
collect2: error: ld returned 1 exit status

Bug: https://bugs.openjdk.java.net/browse/JDK-8167479

Webrev: http://cr.openjdk.java.net/~erikj/8167479/webrev.01/

/Erik