Can't build dart VM with gcc 4.5

[DartBot]

This issue was originally filed by ief...@unipro.ru

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What steps will reproduce the problem?

1. use gcc v4.5
2. Clean checkout of standalone dart vm
3. cd runtime && ../tools/build.py --arch=ia32
    

What is the expected output? What do you see instead?

Expected output: sucessful biuld
I see:
cc1plus: warnings being treated as errors
../runtime/vm/dart_api_impl.cc: In function 'bool dart::Dart_Initialize(int, const char**, void* ()(void))':
../runtime/vm/dart_api_impl.cc:211:67: error: declaration of 'bool dart::Dart_Initialize(int, const char**, void* ()(void))' with C language linkage
../runtime/include/dart_api.h:259:18: error: conflicts with previous declaration 'bool Dart_Initialize(int, char**, void* ()(void))'
CXX(target) out/Debug_ia32/obj.target/libdart_lib/runtime/lib/object.o
make: *** [out/Debug_ia32/obj.target/libdart_api/runtime/vm/dart_api_impl.o] Error 1
make: *** Waiting for unfinished jobs....
make -j 6 BUILDTYPE=Debug_ia32 all
BUILD FAILED

What version of the product are you using? On what operating system?
Ubuntu 11.04, gcc 4.5

Please provide any additional information below.
It looks like the build was broken at r1550

See diff:
http://code.google.com/p/dart/source/diff?spec=svn1550&r=1550&format=side&path=/branches/bleeding_edge/dart/runtime/vm/dart_api_impl.cc&old_path=/branches/bleeding_edge/dart/runtime/vm/dart_api_impl.cc&old=1499

Corresponding .h was not changed

[DartBot]

This comment was originally written by @chrisbu

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Also, runtime/bin/main.cc and runtime/bin/gen_snapshot need updating to remove the const_cast when this gets changed (see todo items).

[ghost]

Set owner to @a-siva.
Added Area-VM, Triaged labels.

[a-siva]

http://codereview.chromium.org//8574075

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Added Fixed label.