Revert 227347 "Run strip via xcrun."

Revert 227347 "Run strip via xcrun."

When the SDK is set to something that Xcode doesn't know about (such as 10.6),
xcrun doesn't work correctly.

mark@cougar bash$ xcrun strip
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/strip: no files specified
mark@cougar bash$ SDKROOT=/SDKs/MacOSX10.6.sdk xcrun strip
xcodebuild: error: SDK "/SDKs/MacOSX10.6.sdk" cannot be located.
xcrun: error: unable to find utility "strip", not a developer tool or in PATH

> Run strip via xcrun.
> 
> In Xcode 5, strip is no longer in SYSTEM_DEVELOPER_BIN_DIR. It is only in
> DT_TOOLCHAIN_DIR. I also checked Xcode 4.6.1 and found that DT_TOOLCHAIN_DIR
> was also set there, and strip is in both SYSTEM_DEVELOPER_BIN_DIR and
> DT_TOOLCHAIN_DIR in that version.
> 
> Environment variables as set when Xcode is installed at /Applications/Xcode.app:
> 
> SYSTEM_DEVELOPER_BIN_DIR=/Applications/Xcode.app/Contents/Developer/usr/bin
> DT_TOOLCHAIN_DIR=/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefa
> ult.xctoolchain
> 
> xcrun should be able to find strip without having to resort to manual
> environment interpretation.
> 
> R=thakis@chromium.org
> 
> Review URL: https://codereview.chromium.org/24352006

TBR=mark@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=227524