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...