I am trying out the ported gcc 4.2, and while compiling our project I noticed some issues which I believe are compiler-
related:

1. Trouble with copy constructors:

/usr/qnx630/host/qnx6/x86/usr/bin/QCC -Wp,-MD,x86/ServerSocket.dep -V4.2.1,gcc_ntox86 -I/trunk -g -Wno-uninitialized -o 
x86/ServerSocket.o -c ServerSocket.cpp
In file included from /usr/qnx630/target/qnx6/usr/include/cpp/xiosbase:7,
                 from /usr/qnx630/target/qnx6/usr/include/cpp/streambuf:7,
                 from /usr/qnx630/target/qnx6/usr/include/cpp/xlocnum:10,
                 from /usr/qnx630/target/qnx6/usr/include/cpp/ios:7,
                 from /usr/qnx630/target/qnx6/usr/include/cpp/ostream:7,
                 from /usr/qnx630/target/qnx6/usr/include/cpp/istream:7,
                 from /usr/qnx630/target/qnx6/usr/include/cpp/string:7,
                 from /usr/qnx630/target/qnx6/usr/include/boost/function/function_base.hpp:14,
                 from /usr/qnx630/target/qnx6/usr/include/boost/function/detail/prologue.hpp:16,
                 from /usr/qnx630/target/qnx6/usr/include/boost/function.hpp:22,
                 from ServerSocket.h:15,
                 from ServerSocket.cpp:15:
/usr/qnx630/target/qnx6/usr/include/yvals.h: In copy constructor 'std::_Locinfo::_Locinfo(const std::_Locinfo&)':
/usr/qnx630/target/qnx6/usr/include/yvals.h:301: error: 'std::_Lockit::_Lockit(const std::_Lockit&)' is private
/usr/qnx630/target/qnx6/usr/include/cpp/xlocinfo:49: error: within this context
/usr/qnx630/target/qnx6/usr/include/cpp/xlocale: In constructor 'std::codecvt<wchar_t, 
char, _Mbstatet>::codecvt(std::size_t)':
/usr/qnx630/target/qnx6/usr/include/cpp/xlocale:683: note: synthesized method 'std::_Locinfo::_Locinfo(const std::
_Locinfo&)' first required here 
cc: /usr/qnx630/host/qnx6/x86/usr/lib/gcc/i386-pc-nto-qnx6.3.0/4.2.1/cc1plus error 1

Class _Locinfo contains a _Lockit member, which has a private, undefined copy constructor, but _Locinfo does not. Then 
when the compiler tries to generate the copy constructor for _Locinfo, it fails. I'm not sure why the compiler is 
generating a copy constructor; perhaps that is the problem. The code in xlocale is similar to the following:

class codecvt
{
void _Init(const _Locinfo &)
{
}

codecvt()
{
  _Init(_Locinfo()); // copy constructor is generated due to this line (why?)
}
}

I solved this problem by altering _Locinfo to have a private copy constructor, and modifying the files that reference it
 so that the copy constructor is not called (changed _Init(_Locinfo()) to _Locinfo info; _Init(info);)

2. Problems linking:

/usr/qnx630/host/qnx6/x86/usr/bin/QCC -V4.2.1,gcc_ntox86 -o x86/select x86/select.o -Lx86 -Wl,-rpath,x86 -lsocket -
lcppunit
x86/select.o: In function `void boost::function1<void, ClientSocket*, std::allocator<void> >::assign_to<void (*
)(ClientSocket*)>(void (*)(ClientSocket*))':
/usr/qnx630/target/qnx6/usr/include/boost/function/function_template.hpp:645: undefined reference to `
__cxa_guard_acquire'
/usr/qnx630/target/qnx6/usr/include/boost/function/function_template.hpp:645: undefined reference to `
__cxa_guard_release'
cc: /usr/qnx630/host/qnx6/x86/usr/bin/ntox86-ld-2.17 error 1

You can see that the problem involves the Boost library. I am using the latest version of Boost (1.34.1). The problem 
seems to be due to a static variable declaration in a function. I solved this problem by adding -fno-threadsafe-statics 
to the compile flags.

3. Problems with exceptions:

Example code:
----- ex.cpp -----
#include <string>

class MyClass
{
public:
        MyClass(std::string in) {} // no error if the parameter is an int
};

class MyException
{
        MyException() {} // no error if there is no constructor defined
};

int main()
{
        try
        {
                MyClass test("asdf"); // no error if this line is commented out
        }
        catch(MyException e) // no error if the...