Error building qt 4.8 custom flags

[jrch2k10]

hi guys im trying to build qt 4.8 with custom flags(i know custom flags are not supported but im curious about these errors)
here is my configure line.

i know my try is pretty bleeding edge i just want to optimize QT as much as i can just for fun so no biggie

./configure --prefix=/usr -qpa -release -opensource -shared -largefile -stl -plugin-sql-mysql -plugin-sql-psql -plugin-sql-sqlite -system-sqlite -no-qt3support -xmlpatterns -multimedia -audio-backend -phonon -phonon-backend -svg -webkit -javascript-jit -script -scripttools -declarative -graphicssystem raster -system-zlib -system-libtiff -system-libpng -system-libmng -system-libjpeg -openssl-linked -optimized-qmake -cups -dbus-linked -reduce-relocations -gtkstyle -openvg -sm -xshape -xinerama -xfixes -xrender -xrandr -mitshm -xinput -xkb -glib -pch

cflags
-Ofast -g0 -mtune=native -m3dnow -msse -msse2 -msse3 -msse4a -mfpmath=sse -msseregparm -pipe -m64

gcc
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-unknown-linux-gnu/4.7.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ./configure --prefix=/usr --enable-languages=c,c++ --enable-threads=posix --enable-tls --enable-libgomp --enable-lto --disable-nls --disable-checking --disable-multilib --disable-bootstrap
Thread model: posix
gcc version 4.7.0 20111210 (experimental) (GCC)

error
g++ -c -include .pch/release-shared/QtXmlPatterns -Ofast -g0 -mtune=native -m3dnow -msse -msse2 -msse3 -msse4a -mfpmath=sse -msseregparm -pipe -m64 -pipe -O2 -fvisibility=hidden -fvisibility-inlines-hidden -Wall -W -D_REENTRANT -fPIC -DQT_SHARED -DQT_NO_CORESERVICES -DQT_BUILD_XMLPATTERNS_LIB -DQT_NO_USING_NAMESPACE -DQT_NO_CAST_TO_ASCII -DQT_ASCII_CAST_WARNINGS -DQT_MOC_COMPAT -DQT_USE_QSTRINGBUILDER -DQT_NO_DEBUG -DQT_NETWORK_LIB -DQT_CORE_LIB -DQT_HAVE_MMX -DQT_HAVE_3DNOW -DQT_HAVE_SSE -DQT_HAVE_MMXEXT -DQT_HAVE_SSE2 -DQT_HAVE_SSE3 -DQT_HAVE_SSSE3 -DQT_HAVE_SSE4_1 -DQT_HAVE_SSE4_2 -DQT_HAVE_AVX -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -I../../mkspecs/linux-g++-64 -I. -I../../include/QtCore -I../../include/QtNetwork -I../../include -I../../include/QtXmlPatterns -I.rcc/release-shared -Iacceltree -Idata -Iapi -Ienvironment -Iexpr -Ifunctions -Iiterators -Ijanitors -Iparser -Ischema -Itype -Iutils -I.moc/release-shared -o .obj/release-shared/qbuiltinatomictypes.o type/qbuiltinatomictypes.cpp
In file included from type/qbuiltinatomictypes_p.h:55:0,
from type/qbuiltinatomictypes.cpp:45:
type/qatomiccasterlocators_p.h:570:46: error: 'virtual QPatternist::AtomicTypeVisitorResult::Ptr QPatternist::ToDerivedIntegerCasterLocator<type>::visit(const QPatternist::BooleanType*, const QPatternist::SourceLocationReflection*) const' cannot be overloaded
type/qatomiccasterlocators_p.h:295:46: error: with 'virtual QPatternist::AtomicTypeVisitorResult::Ptr QPatternist::ToIntegerCasterLocator::visit(const QPatternist::BooleanType*, const QPatternist::SourceLocationReflection*) const'
type/qatomiccasterlocators_p.h:577:46: error: 'virtual QPatternist::AtomicTypeVisitorResult::Ptr QPatternist::ToDerivedIntegerCasterLocator<type>::visit(const QPatternist::StringType*, const QPatternist::SourceLocationReflection*) const' cannot be overloaded
type/qatomiccasterlocators_p.h:305:46: error: with 'virtual QPatternist::AtomicTypeVisitorResult::Ptr QPatternist::ToIntegerCasterLocator::visit(const QPatternist::StringType*, const QPatternist::SourceLocationReflection*) const'
type/qatomiccasterlocators_p.h:584:46: error: 'virtual QPatternist::AtomicTypeVisitorResult::Ptr QPatternist::ToDerivedIntegerCasterLocator<type>::visit(const QPatternist::AnyURIType*, const QPatternist::SourceLocationReflection*) const' cannot be overloaded
In file included from type/qatomictype_p.h:56:0,
from type/qanynodetype_p.h:55,
from type/qbuiltintypes_p.h:55,
from type/qbuiltinatomictypes.cpp:43:

[guardian]

same trouble. In fact i just need to put

QMAKE_CXXFLAGS_RELEASE = -Ofast
and it fails

while

QMAKE_CXXFLAGS_RELEASE = -O2
works fine

the only errors showing up is:
"xxx.o error1"
where xxx.cpp holds the main function

EDIT:
SOrry, not the same problem in fact...