Q:

XCode 3.x to 4.0 upgrade issue

I have just upgraded XCode 3.x to 4.0 and ran into following build error.
Command /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2 failed with exit code 1

I tried juggling around this error but couldn't get rid of it. Does anyone know fix for this please?
Complete error message:

Ld
  /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos/myApp.app/myApp
  normal armv7 cd "/xcode -
  svn/TheAppStudio/TheAppStudio" setenv
  IPHONEOS_DEPLOYMENT_TARGET 4.2 setenv
  PATH
  "/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
  /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2
  -arch armv7 -isysroot /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.3.sdk
  -L/Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos
  -F/Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos
  -filelist /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Intermediates/myApp.build/Debug-iphoneos/myApp.build/Objects-normal/armv7/myApp.LinkFileList
  -dead_strip -all_load -ObjC -miphoneos-version-min=4.2 -framework Foundation -framework UIKit -framework
  CoreGraphics -framework QuartzCore
  /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos/libThree20.a
  /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos/libThree20Core.a
  /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos/libThree20Network.a
  /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos/libThree20Style.a
  /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos/libThree20UI.a
  /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos/libThree20UICommon.a
  /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos/libThree20UINavigator.a
  -framework Security -framework SystemConfiguration -framework
  MessageUI -framework AVFoundation
  -framework MediaPlayer -framework CoreLocation -framework CoreLocation
  -framework MapKit -framework CFNetwork -framework AudioToolbox -lz.1.2.3 -framework MobileCoreServices -lxml2 -o /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos/myApp.app/myApp
arm-apple-darwin10-gcc-4.2.1:
  /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos/libThree20.a:
  No such file or directory
  arm-apple-darwin10-gcc-4.2.1:
  /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos/libThree20Core.a:
  No such file or directory
  arm-apple-darwin10-gcc-4.2.1:
  /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos/libThree20Network.a:
  No such file or directory
  arm-apple-darwin10-gcc-4.2.1:
  /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos/libThree20Style.a:
  No such file or directory
  arm-apple-darwin10-gcc-4.2.1:
  /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos/libThree20UI.a:
  No such file or directory
  arm-apple-darwin10-gcc-4.2.1:
  /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos/libThree20UICommon.a:
  No such file or directory
  arm-apple-darwin10-gcc-4.2.1:
  /Users/xxx/Library/Developer/Xcode/DerivedData/myApp-ddoknnyqnanytlcpbqpazmjjqbpx/Build/Products/Debug-iphoneos/libThree20UINavigator.a:
  No such file or directory Command
  /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2
  failed with exit code 1

Thanks.
PS: I tried cleaning up the solution and also verified Library Search path is the same as another machine where it works fine.

A:

I have sorted this out. The situation was littel bit weird. The three20 libraries base SDK was setup to iphonesimulator and hence, it was generating *.a files for simulator path ..../Debug-iphonesimulator but my project was trying to look them on .../Debug-iphoneos path. The three20 library wasn't allowing me to build for iPhone unless I had removed iphonesimulator from supported platform and changed base SDK to iphones. Rebuild all three20 projects individually and then it worked fine!!

