Request for review: support building hotspot with gcc 4.6

[Omair Majid]

Hi,

http://cr.openjdk.java.net/~omajid/webrevs/gcc-46-support/

The patch adds support for building hotspot with gcc 4.6. gcc 4.6 
changed how arguments are handled. It now treats -export-dynamic as it 
treats any other -efoo option: it thinks xport-dynamic is the entry 
point and passes this information to the linker. Since -export-dynamic 
is not passed to the linker, not all symbols will be exported by the 
linker. The bfd-based linker, given the invalid entry point 
xport-dynamic, simply ignores it. The gold linker, however, crashes 
causing the build to fail.

Since -export-dynamic is a linker option, the correct way to pass it is 
using -Wl,-export-dynamic (or -Xlinker -export-dynamic). We have had 
this patch in IcedTea6 for a while now, but it would be nice if this was 
in OpenJDK too.

Thanks,
Omair