Switch from using PLATFORM_NAME to SDK selectors in ANGLE, bmalloc, gtest, JavaScript...

Switch from using PLATFORM_NAME to SDK selectors in ANGLE, bmalloc, gtest, JavaScriptCore, WTF
<http://webkit.org/b/139212>

Reviewed by Joseph Pecoraro.

Source/bmalloc:

* Configurations/Base.xcconfig:
- Only set GCC_ENABLE_OBJC_GC, GCC_MODEL_TUNING and TOOLCHAINS
  on OS X.
* Configurations/DebugRelease.xcconfig:
- Only set MACOSX_DEPLOYMENT_TARGET and SDKROOT on OS X.

Source/JavaScriptCore:

* Configurations/Base.xcconfig:
- Only set GCC_ENABLE_OBJC_GC, GCC_MODEL_TUNING and TOOLCHAINS
  on OS X.
- Only set LLVM_LOCAL_HEADER_PATH and LLVM_SYSTEM_HEADER_PATH on
  OS X.
- Set JAVASCRIPTCORE_CONTENTS_DIR and
  JAVASCRIPTCORE_FRAMEWORKS_DIR separately for iOS and OS X.

* Configurations/DebugRelease.xcconfig:
- Only set MACOSX_DEPLOYMENT_TARGET and SDKROOT on OS X.

* Configurations/JSC.xcconfig:
- Only set CODE_SIGN_ENTITLEMENTS for iOS hardware builds.

* Configurations/JavaScriptCore.xcconfig:
- Set OTHER_LDFLAGS separately for iOS and OS X.
- Set SECTORDER_FLAGS separately for iOS and OS X, but only for
  Production builds.
- Only set EXCLUDED_SOURCE_FILE_NAMES for iOS.

* Configurations/LLVMForJSC.xcconfig:
- Rename LLVM_LIBS_iphoneos to LLVM_LIBS_ios.
- Set LLVM_LIBRARY_PATHS and OTHER_LDFLAGS_LLVM_ENABLE_FTL_JIT
  separately for iOS hardware and OS X.
- Fix curly braces in LIBRARY_SEARCH_PATHS.
- Merge OTHER_LDFLAGS_BASE into OTHER_LDFLAGS. (Could have been
  done before this patch.)

* Configurations/ToolExecutable.xcconfig:
- Only set CODE_SIGN_ENTITLEMENTS for iOS, per target.
- Only set CLANG_ENABLE_OBJC_ARC for i386 on the iOS Simulator.
- Add missing newline.

* Configurations/Version.xcconfig:
- Set SYSTEM_VERSION_PREFIX separately for iOS and OS X.

Source/ThirdParty:

* gtest/xcode/Config/General.xcconfig:
- Only set SDKROOT and TOOLCHAINS on OS X.

Source/ThirdParty/ANGLE:

* Configurations/Base.xcconfig:
- Only set GCC_ENABLE_OBJC_GC, GCC_MODEL_TUNING and TOOLCHAINS
  on OS X.
* Configurations/DebugRelease.xcconfig:
- Only set MACOSX_DEPLOYMENT_TARGET and SDKROOT on OS X.

Source/WTF:

* Configurations/Base.xcconfig:
- Only set GCC_ENABLE_OBJC_GC, GCC_MODEL_TUNING and TOOLCHAINS
  on OS X.
* Configurations/DebugRelease.xcconfig:
- Only set MACOSX_DEPLOYMENT_TARGET and SDKROOT on OS X.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@177027 268f45cc-cd09-0410-ab3c-d52691b4dbfc