iPhone gcc-4.2 failed with exit code 1

Help, I'm at wits end -- sometimes my Xcode runs -- sometimes it doesn't I keep getting

I installed Xcode 4.1 then upgraded to 4.2

I can't even run a freshly made project :(

ProcessPCH /Users/david/Library/Developer/Xcode/DerivedData/iDecide-eurvfbqsagnsmkgdvuhytbalyxkj/Build/PrecompiledHeaders/iDecide-Prefix-fjnitkqizspbsgezzdhvfinujnhz/iDecide-Prefix.pch.pth iDecide/iDecide-Prefix.pch normal i386 objective-c com.apple.compilers.llvm.clang.1_0.compiler cd /Users/david/Documents/tmp/iDecide setenv LANG en_US.US-ASCII setenv PATH "/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Developer/usr/bin:/Users/david/.rvm/gems/ruby-1.9.2-p180/bin:/Users/david/.rvm/gems/ruby-1.9.2-p180@global/bin:/Users/david/.rvm/rubies/ruby-1.9.2-p180/bin:/Users/david/.rvm/bin:/Users/david/apache-maven-3.0.3/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/X11/bin:/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/bin:/usr/local/Cellar/android-sdk/r15/platform-tools:/Users/david/groovy-1.8.2/bin:/Users/david/grails-1.3.7/bin:/usr/local/lib/node_modules:/usr/local/share/aclocal:/usr/local/Cellar/liquibase/2.0.3/libexec" /usr/bin/gcc-4.2 -x objective-c-header -arch i386 -fmessage-length=0 -fdiagnostics-print-source-range-info -fdiagnostics-show-category=id -fdiagnostics-parseable-fixits -std=gnu99 -fobjc-arc -Wno-trigraphs -fpascal-strings -O0 -Wmissing-prototypes -Wreturn-type -Wparentheses -Wswitch -Wno-unused-parameter -Wunused-variable -Wunused-value -Wno-shorten-64-to-32 -DDEBUG=1 -isysroot /Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator5.0.sdk -fexceptions -fasm-blocks -mmacosx-version-min=10.6 -gdwarf-2 -Wno-sign-conversion -fobjc-abi-version=2 -fobjc-legacy-dispatch "-DIBOutlet= attribute ((iboutlet))" "-DIBOutletCollection(ClassName)= attribute ((iboutletcollection(ClassName)))" "-DIBAction=void) attribute ((ibaction)" -D__IPHONE_OS_VERSION_MIN_REQUIRED=50000 -iquote /Users/david/Library/Developer/Xcode/DerivedData/iDecide-eurvfbqsagnsmkgdvuhytbalyxkj/Build/Intermediates/iDecide.build/Debug-iphonesimulator/iDecide.build/iDecide-generated-files.hmap -I/Users/david/Library/Developer/Xcode/DerivedData/iDecide-eurvfbqsagnsmkgdvuhytbalyxkj/Build/Intermediates/iDecide.build/Debug-iphonesimulator/iDecide.build/iDecide-own-target-headers.hmap -I/Users/david/Library/Developer/Xcode/DerivedData/iDecide-eurvfbqsagnsmkgdvuhytbalyxkj/Build/Intermediates/iDecide.build/Debug-iphonesimulator/iDecide.build/iDecide-all-target-headers.hmap -iquote /Users/david/Library/Developer/Xcode/DerivedData/iDecide-eurvfbqsagnsmkgdvuhytbalyxkj/Build/Intermediates/iDecide.build/Debug-iphonesimulator/iDecide.build/iDecide-project-headers.hmap -I/Users/david/Library/Developer/Xcode/DerivedData/iDecide-eurvfbqsagnsmkgdvuhytbalyxkj/Build/Products/Debug-iphonesimulator/include -I/Users/david/Library/Developer/Xcode/DerivedData/iDecide-eurvfbqsagnsmkgdvuhytbalyxkj/Build/Intermediates/iDecide.build/Debug-iphonesimulator/iDecide.build/DerivedSources/i386 -I/Users/david/Library/Developer/Xcode/DerivedData/iDecide-eurvfbqsagnsmkgdvuhytbalyxkj/Build/Intermediates/iDecide.build/Debug-iphonesimulator/iDecide.build/DerivedSources -F/Users/david/Library/Developer/Xcode/DerivedData/iDecide-eurvfbqsagnsmkgdvuhytbalyxkj/Build/Products/Debug-iphonesimulator -c /Users/david/Documents/tmp/iDecide/iDecide/iDecide-Prefix.pch -o /Users/david/Library/Developer/Xcode/DerivedData/iDecide-eurvfbqsagnsmkgdvuhytbalyxkj/Build/PrecompiledHeaders/iDecide-Prefix-fjnitkqizspbsgezzdhvfinujnhz/iDecide-Prefix.pch.pth -MMD -MT dependencies -MF /Users/david/Library/Developer/Xcode/DerivedData/iDecide-eurvfbqsagnsmkgdvuhytbalyxkj/Build/PrecompiledHeaders/iDecide-Prefix-fjnitkqizspbsgezzdhvfinujnhz/iDecide-Prefix.pch.d

cc1obj: error: unrecognized command line option "-Wno-sign-conversion" cc1obj: error: unrecognized command line option "-fdiagnostics-print-source-range-info" cc1obj: error: unrecognized command line option "-fdiagnostics-show-category=id" cc1obj: error: unrecognized command line option "-fdiagnostics-parseable-fixits" cc1obj: error: unrecognized command line option "-fobjc-arc" Command /usr/bin/gcc-4.2 failed with exit code 1