title: Issue with building project in XCode -- ProcessPCH Error
body: <p>I've been having an issue compiling my project after attempting to install the Facebook SDK to the project. I've reverted the code back to it's previous state, however I'm still getting error messages related to "ProcessPCH". I've checked the Target settings and still cannot find any solution to this issue.</p>
  
  <p>The error code is shown below:</p>
  
  <pre><code>ProcessPCH /Users/admin/Library/Developer/Xcode/DerivedData/AirFranceMusic-btdgsdavrzffuyaockrkcyvdacgq/Build/Intermediates/PrecompiledHeaders/AirFranceMusic-Prefix-acpjajeiwlvgzwgddsqkamtwztjy/AirFranceMusic-Prefix.pch.pth AirFranceMusic/AirFranceMusic-Prefix.pch normal i386 objective-c com.apple.compilers.llvm.clang.1_0.compiler
  cd /Users/admin/Documents/AirFranceMusic/src
  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 -Wformat -Wno-missing-braces -Wparentheses -Wswitch -Wno-unused-function -Wno-unused-label -Wno-unused-parameter -Wunused-variable -Wunused-value -Wuninitialized -Wno-unknown-pragmas -Wno-shadow -Wno-four-char-constants -Wno-conversion -Wno-sign-compare -Wno-shorten-64-to-32 -Wpointer-sign -Wno-newline-eof -Wno-selector -Wno-strict-selector-match -Wno-undeclared-selector -Wno-deprecated-implementations -DDEBUG=1 -DDEBUG=1 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator5.1.sdk -fexceptions -fasm-blocks -Wprotocol -Wdeprecated-declarations -mmacosx-version-min=10.6 -g -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=40000 -I/Users/admin/Library/Developer/Xcode/DerivedData/AirFranceMusic-btdgsdavrzffuyaockrkcyvdacgq/Build/Intermediates/AirFranceMusic.build/Debug-iphonesimulator/AirFranceMusic.build/AirFranceMusic.hmap -I/Users/admin/Library/Developer/Xcode/DerivedData/AirFranceMusic-btdgsdavrzffuyaockrkcyvdacgq/Build/Products/Debug-iphonesimulator/include -I/Users/admin/Library/Developer/Xcode/DerivedData/AirFranceMusic-btdgsdavrzffuyaockrkcyvdacgq/Build/Intermediates/AirFranceMusic.build/Debug-iphonesimulator/AirFranceMusic.build/DerivedSources/i386 -I/Users/admin/Library/Developer/Xcode/DerivedData/AirFranceMusic-btdgsdavrzffuyaockrkcyvdacgq/Build/Intermediates/AirFranceMusic.build/Debug-iphonesimulator/AirFranceMusic.build/DerivedSources -F/Users/admin/Library/Developer/Xcode/DerivedData/AirFranceMusic-btdgsdavrzffuyaockrkcyvdacgq/Build/Products/Debug-iphonesimulator -F/Users/admin/Documents/AirFranceMusic/src --serialize-diagnostics /Users/admin/Library/Developer/Xcode/DerivedData/AirFranceMusic-btdgsdavrzffuyaockrkcyvdacgq/Build/Intermediates/PrecompiledHeaders/AirFranceMusic-Prefix-acpjajeiwlvgzwgddsqkamtwztjy/AirFranceMusic-Prefix.pch.dia -c /Users/admin/Documents/AirFranceMusic/src/AirFranceMusic/AirFranceMusic-Prefix.pch -o /Users/admin/Library/Developer/Xcode/DerivedData/AirFranceMusic-btdgsdavrzffuyaockrkcyvdacgq/Build/Intermediates/PrecompiledHeaders/AirFranceMusic-Prefix-acpjajeiwlvgzwgddsqkamtwztjy/AirFranceMusic-Prefix.pch.pth -MMD -MT dependencies -MF /Users/admin/Library/Developer/Xcode/DerivedData/AirFranceMusic-btdgsdavrzffuyaockrkcyvdacgq/Build/Intermediates/PrecompiledHeaders/AirFranceMusic-Prefix-acpjajeiwlvgzwgddsqkamtwztjy/AirFranceMusic-Prefix.pch.d
  
  In file included from /Users/admin/Documents/AirFranceMusic/src/AirFranceMusic/AirFranceMusic-Prefix.pch:20:
  In file included from /Users/admin/Documents/AirFranceMusic/src/AirFranceMusic/../../libs/MKNetworkKit/MKNetworkKit.h:52:
  /Users/admin/Documents/AirFranceMusic/src/AirFranceMusic/../../libs/MKNetworkKit/Categories/NSString+MKNetworkKitAdditions.h:26:1: error: missing '@end'
  @interface NSString (MKNetworkKitAdditions)
  ^
  @end
  
  /Users/admin/Documents/AirFranceMusic/src/AirFranceMusic/AppDelegate.h:16:1: note: class started here
  @interface AppDelegate : UIResponder &lt;UIApplicationDelegate, UITabBarControllerDelegate&gt;
  ^
  In file included from /Users/admin/Documents/AirFranceMusic/src/AirFranceMusic/AirFranceMusic-Prefix.pch:20:
  In file included from /Users/admin/Documents/AirFranceMusic/src/AirFranceMusic/../../libs/MKNetworkKit/MKNetworkKit.h:52:
  /Users/admin/Documents/AirFranceMusic/src/AirFranceMusic/../../libs/MKNetworkKit/Categories/NSString+MKNetworkKitAdditions.h:26:21: error: method type specifier must start with '-' or '+'
  @interface NSString (MKNetworkKitAdditions)
                      ^
  /Users/admin/Documents/AirFranceMusic/src/AirFranceMusic/../../libs/MKNetworkKit/Categories/NSString+MKNetworkKitAdditions.h:26:22: error: expected a type
  @interface NSString (MKNetworkKitAdditions)
                       ^
  /Users/admin/Documents/AirFranceMusic/src/AirFranceMusic/../../libs/MKNetworkKit/Categories/NSString+MKNetworkKitAdditions.h:28:1: error: expected selector for Objective-C method
  - (NSString *) md5;
  ^
  4 errors generated.
  </code></pre>
  
  <p>If anyone has a solution for this, it would be greatly appreciated.</p>