incompatible with gcc-4.3 --std=gnu++0x (partial stdc++11 support)

The qtconcurrentrun.h wants to optimize when stdc++11 features
are available but the ifdef is only guarded by Q_COMPILER_DECLTYPE.

That Q_COMPILER_DECLTYPE is defined in qglobals.h if gcc >= 4.3
but the qtconcurrentrun.h source text does also use the new
function decleration syntax ("foo() -> result") which is only
available if gcc >= 4.4.

Therefore, enabling stdc++11 support on gcc-4.3 will make any
Qt program to fail immediately. Tested on current SLES 11 SP2.

> make good
{ echo "#include <QtCore>" ; echo "int main() {}"; } > good.cpp
/usr/bin/gcc-4.3 -I/usr/include/Qt good.cpp -c -o good.o

> make fail
{ echo "#include <QtCore>" ; echo "int main() {}"; } > fail.cpp
/usr/bin/gcc-4.3 -I/usr/include/Qt -std=gnu++0x fail.cpp -c -o fail.o

In file included from /usr/include/Qt/QtCore:62,
from fail.cpp:1:
/usr/include/Qt/qtconcurrentrun.h:105: error: expected initializer before ‘->’ token
/usr/include/Qt/qtconcurrentrun.h:113: error: expected initializer before ‘->’ token
/usr/include/Qt/qtconcurrentrun.h:121: error: expected initializer before ‘->’ token
/usr/include/Qt/qtconcurrentrun.h:129: error: expected initializer before ‘->’ token
/usr/include/Qt/qtconcurrentrun.h:137: error: expected initializer before ‘->’ token
/usr/include/Qt/qtconcurrentrun.h:145: error: expected initializer before ‘->’ token
make: *** [fail] Fehler 1

> cat /etc/issue

Welcome to SUSE Linux Enterprise Server 11 SP2 (x86_64) - Kernel \r (\l).

> rpm -q --whatprovides /usr/include/Qt/qtconcurrentrun.h
libqt4-devel-4.8.4-284.1

> rpm -q --whatprovides /usr/bin/gcc
gcc-4.3-62.198