Clang falló con el error de código de salida 1 en el objective c

¿Qué es este error? Estoy intentando convertir un proyecto que no sea ARC en un proyecto de arco y se muestra un error.
Command /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang failed with exit code 1

 ProcessPCH /Users/amit/Library/Developer/Xcode/DerivedData/Corlocation-gfdftvxjfdzkejebtysirafavnmv/Build/Intermediates/PrecompiledHeaders/Corlocation-Prefix-fjwexhbcqsylinfenhkyculomcng/Corlocation-Prefix.pch.pth Corlocation/Corlocation-Prefix.pch normal i386 objective-c com.apple.compilers.llvm.clang.1_0.compiler cd "/Users/amit/Desktop/My Apps/Corlocation" setenv LANG en_US.US-ASCII setenv PATH "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin" /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -x objective-c-header -arch i386 -fmessage-length=0 -std=gnu99 -fobjc-arc -Wno-trigraphs -fpascal-strings -O0 -Wno-missing-field-initializers -Wno-missing-prototypes -Wreturn-type -Wno-implicit-atomic-properties -Wno-receiver-is-weak -Wduplicate-method-match -Wformat -Wno-missing-braces -Wparentheses -Wswitch -Wno-unused-function -Wno-unused-label -Wno-unused-parameter -Wunused-variable -Wunused-value -Wempty-body -Wuninitialized -Wno-unknown-pragmas -Wno-shadow -Wno-four-char-constants -Wno-conversion -Wno-shorten-64-to-32 -Wpointer-sign -Wno-newline-eof -Wno-selector -Wno-strict-selector-match -Wno-undeclanetworking-selector -Wno-deprecated-implementations -DDEBUG=1 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.0.sdk -fexceptions -fasm-blocks -Wprotocol -Wdeprecated-declarations -g -Wno-sign-conversion -fobjc-abi-version=2 -fobjc-legacy-dispatch "-DIBOutlet=__attribute__((iboutlet))" "-DIBOutletCollection(ClassName)=__attribute__((iboutletcollection(ClassName)))" "-DIBAction=void)__attribute__((ibaction)" -mios-simulator-version-min=6.0 -iquote /Users/amit/Library/Developer/Xcode/DerivedData/Corlocation-gfdftvxjfdzkejebtysirafavnmv/Build/Intermediates/Corlocation.build/Debug-iphonesimulator/Corlocation.build/Corlocation-generated-files.hmap -I/Users/amit/Library/Developer/Xcode/DerivedData/Corlocation-gfdftvxjfdzkejebtysirafavnmv/Build/Intermediates/Corlocation.build/Debug-iphonesimulator/Corlocation.build/Corlocation-own-target-headers.hmap -I/Users/amit/Library/Developer/Xcode/DerivedData/Corlocation-gfdftvxjfdzkejebtysirafavnmv/Build/Intermediates/Corlocation.build/Debug-iphonesimulator/Corlocation.build/Corlocation-all-target-headers.hmap -iquote /Users/amit/Library/Developer/Xcode/DerivedData/Corlocation-gfdftvxjfdzkejebtysirafavnmv/Build/Intermediates/Corlocation.build/Debug-iphonesimulator/Corlocation.build/Corlocation-project-headers.hmap -I/Users/amit/Library/Developer/Xcode/DerivedData/Corlocation-gfdftvxjfdzkejebtysirafavnmv/Build/Products/Debug-iphonesimulator/include -I/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include -I/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include -I/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include -I/Users/amit/Library/Developer/Xcode/DerivedData/Corlocation-gfdftvxjfdzkejebtysirafavnmv/Build/Intermediates/Corlocation.build/Debug-iphonesimulator/Corlocation.build/DerivedSources/i386 -I/Users/amit/Library/Developer/Xcode/DerivedData/Corlocation-gfdftvxjfdzkejebtysirafavnmv/Build/Intermediates/Corlocation.build/Debug-iphonesimulator/Corlocation.build/DerivedSources -F/Users/amit/Library/Developer/Xcode/DerivedData/Corlocation-gfdftvxjfdzkejebtysirafavnmv/Build/Products/Debug-iphonesimulator fno-objc-arc --serialize-diagnostics /Users/amit/Library/Developer/Xcode/DerivedData/Corlocation-gfdftvxjfdzkejebtysirafavnmv/Build/Intermediates/PrecompiledHeaders/Corlocation-Prefix-fjwexhbcqsylinfenhkyculomcng/Corlocation-Prefix.pch.dia -c "/Users/amit/Desktop/My Apps/Corlocation/Corlocation/Corlocation-Prefix.pch" -o /Users/amit/Library/Developer/Xcode/DerivedData/Corlocation-gfdftvxjfdzkejebtysirafavnmv/Build/Intermediates/PrecompiledHeaders/Corlocation-Prefix-fjwexhbcqsylinfenhkyculomcng/Corlocation-Prefix.pch.pth -MMD -MT dependencies -MF /Users/amit/Library/Developer/Xcode/DerivedData/Corlocation-gfdftvxjfdzkejebtysirafavnmv/Build/Intermediates/PrecompiledHeaders/Corlocation-Prefix-fjwexhbcqsylinfenhkyculomcng/Corlocation-Prefix.pch.d clang: error: no such file or directory: 'fno-objc-arc' Command /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang failed with exit code 1 

usted usa el fno-objc-arc que es un argumento de línea de command, probablemente necesite prefijarlo con un guión, como con:

Reemplace fno-objc-arc a -fno-objc-arc

fno-objc-arc debe ser -fno-objc-arc y se utiliza para desactivar ARC para el file, por lo que obviamente hay un error en la configuration de su proyecto Xcode.

Vea la captura de pantalla en esta pregunta SO para get detalles sobre dónde está configurado.