Bug#746907: qtwebkit: ftbfs with GCC-4.9

[Matthias Klose <doko@debian.org>]

Package: src:qtwebkit
Version: 2.2.1-7
Severity: important
Tags: sid jessie
User: debian-gcc@lists.debian.org
Usertags: ftbfs-gcc-4.9

The package fails to build in a test rebuild on at least amd64 with
gcc-4.9/g++-4.9, but succeeds to build with gcc-4.8/g++-4.8. The
severity of this report may be raised before the jessie release.

The full build log can be found at:
http://people.debian.org/~doko/logs/failed-gcc49/qtwebkit_2.2.1-7_unstable_gcc49.log
The last lines of the build log are at the end of this report.

To build with GCC 4.9, either set CC=gcc-4.9 CXX=g++-4.9 explicitly,
or install the gcc, g++, gfortran, ... packages from experimental.

  apt-get -t experimental install g++ 

Common build failures are new warnings resulting in build failures
with -Werror turned on, or new/dropped symbols in Debian symbols
files.  For other C/C++ related build failures see the porting guide
at http://gcc.gnu.org/gcc-4.9/porting_to.html

[...]
../JavaScriptCore/wtf/PassOwnPtr.h: In member function 'bool WTF::PassOwnPtr<T>::operator!=(const WTF::PassOwnPtr<U>&)':
../JavaScriptCore/wtf/Assertions.h:326:47: warning: typedef 'dummyOwnPtrs_should_never_be_equal' locally defined but not used [-Wunused-local-typedefs]
 #define COMPILE_ASSERT(exp, name) typedef int dummy##name [(exp) ? 1 : -1]
                                               ^
../JavaScriptCore/wtf/PassOwnPtr.h:96:70: note: in expansion of macro 'COMPILE_ASSERT'
         template<typename U> bool operator!=(const PassOwnPtr<U>&) { COMPILE_ASSERT(!sizeof(U*), OwnPtrs_should_never_be_equal); return false; }
                                                                      ^
../JavaScriptCore/wtf/PassOwnPtr.h: In member function 'bool WTF::PassOwnPtr<T>::operator==(const WTF::OwnPtr<U>&)':
../JavaScriptCore/wtf/Assertions.h:326:47: warning: typedef 'dummyOwnPtrs_should_never_be_equal' locally defined but not used [-Wunused-local-typedefs]
 #define COMPILE_ASSERT(exp, name) typedef int dummy##name [(exp) ? 1 : -1]
                                               ^
../JavaScriptCore/wtf/PassOwnPtr.h:97:66: note: in expansion of macro 'COMPILE_ASSERT'
         template<typename U> bool operator==(const OwnPtr<U>&) { COMPILE_ASSERT(!sizeof(U*), OwnPtrs_should_never_be_equal); return false; }
                                                                  ^
../JavaScriptCore/wtf/PassOwnPtr.h: In member function 'bool WTF::PassOwnPtr<T>::operator!=(const WTF::OwnPtr<U>&)':
../JavaScriptCore/wtf/Assertions.h:326:47: warning: typedef 'dummyOwnPtrs_should_never_be_equal' locally defined but not used [-Wunused-local-typedefs]
 #define COMPILE_ASSERT(exp, name) typedef int dummy##name [(exp) ? 1 : -1]
                                               ^
../JavaScriptCore/wtf/PassOwnPtr.h:98:66: note: in expansion of macro 'COMPILE_ASSERT'
         template<typename U> bool operator!=(const OwnPtr<U>&) { COMPILE_ASSERT(!sizeof(U*), OwnPtrs_should_never_be_equal); return false; }
                                                                  ^
../JavaScriptCore/runtime/JSVariableObject.h: In constructor 'JSC::JSVariableObject::JSVariableObject(JSC::JSGlobalData&, JSC::Structure*, JSC::SymbolTable*, JSC::Register*)':
../JavaScriptCore/wtf/Assertions.h:326:47: warning: typedef 'dummyRegister_should_be_same_size_as_WriteBarrier' locally defined but not used [-Wunused-local-typedefs]
 #define COMPILE_ASSERT(exp, name) typedef int dummy##name [(exp) ? 1 : -1]
                                               ^
../JavaScriptCore/runtime/JSVariableObject.h:75:13: note: in expansion of macro 'COMPILE_ASSERT'
             COMPILE_ASSERT(sizeof(WriteBarrier<Unknown>) == sizeof(Register), Register_should_be_same_size_as_WriteBarrier);
             ^
../JavaScriptCore/runtime/JSGlobalObject.h: In constructor 'JSC::JSGlobalObject::JSGlobalObject(JSC::JSGlobalData&, JSC::Structure*)':
../JavaScriptCore/wtf/Assertions.h:326:47: warning: typedef 'dummyJSGlobalObject_has_only_a_single_slot' locally defined but not used [-Wunused-local-typedefs]
 #define COMPILE_ASSERT(exp, name) typedef int dummy##name [(exp) ? 1 : -1]
                                               ^
../JavaScriptCore/runtime/JSGlobalObject.h:127:13: note: in expansion of macro 'COMPILE_ASSERT'
             COMPILE_ASSERT(JSGlobalObject::AnonymousSlotCount == 1, JSGlobalObject_has_only_a_single_slot);
             ^
../JavaScriptCore/runtime/JSGlobalObject.h: In constructor 'JSC::JSGlobalObject::JSGlobalObject(JSC::JSGlobalData&, JSC::Structure*, JSC::JSObject*)':
../JavaScriptCore/wtf/Assertions.h:326:47: warning: typedef 'dummyJSGlobalObject_has_only_a_single_slot' locally defined but not used [-Wunused-local-typedefs]
 #define COMPILE_ASSERT(exp, name) typedef int dummy##name [(exp) ? 1 : -1]
                                               ^
../JavaScriptCore/runtime/JSGlobalObject.h:140:13: note: in expansion of macro 'COMPILE_ASSERT'
             COMPILE_ASSERT(JSGlobalObject::AnonymousSlotCount == 1, JSGlobalObject_has_only_a_single_slot);
             ^
make[3]: Leaving directory `/«PKGBUILDDIR»/Source/WebCore'
make[2]: *** [sub-WebCore-make_default-ordered] Error 2
make[2]: Leaving directory `/«PKGBUILDDIR»/Source'
dh_auto_build: make -j10 returned exit code 2
make[1]: *** [override_dh_auto_build] Error 2
make[1]: Leaving directory `/«PKGBUILDDIR»'
make: *** [build-arch] Error 2
dpkg-buildpackage: error: debian/rules build-arch gave error exit status 2