[MacPorts] #29172: remove dependency on Xcode

[MacPorts]

#29172: remove dependency on Xcode
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  Reporter:  joshmoz@…    |      Owner:  macports-tickets@…
      Type:  enhancement  |     Status:  new
  Priority:  Normal       |  Milestone:
 Component:  base         |    Version:
Resolution:               |   Keywords:
      Port:               |
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Comment (by mfeiri@…):

 After a batch of changes we now have something like a pure open source SDK
 in ${destroot}${prefix}/Developer/SDKs/Darwin${os.major}.sdk. The relevant
 ports are CarbonHeaders, csu, libc-headers, libm-headers, libunwind-
 headers, and xnu-headers. I didn't yet try to uninstall Xcode to really
 verify this, but it appears possible now to build basic applications
 without Xcode. This works for me on my machine (OS X 10.9):

 {{{clang-mp-3.5 helloworld.c -isysroot
 /opt/local/Developer/SDKs/Darwin13.sdk --sysroot /}}}

 Plenty of work/opportunities for future enhancements exist:
  * Package open source headers for 10.10 SDK if and when Apple provides
 them
  * Improve coverage relative to the official OS X SDK, e.g. provide
 libraries and more headers
  * Offer versioned DarwinXX.sdk ports instead of a bunch of header ports
 for the current host system, e.g. to enable cross-compilation
  * Provide substitutes for xcodebuild (e.g. xctool) and other relevant
 developer tools.
  * Introduce a way for ports to indicate if they can be built with a pure
 open source SDK or if proprietary frameworks are required.

-- 
Ticket URL: <https://trac.macports.org/ticket/29172#comment:18>
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