cmake on arm64

[peter green <plugwash@p10link.net>]

The latest upload of cmake for arm64 failed to build (and stuff is 
piling up behind it).

239/307 Test #246: RunCMake.Syntax ..................................***Failed    0.41 sec
-- CommandSpaces - PASSED
-- CommandTabs - PASSED
-- CommandNewlines - PASSED
CMake Error at /«PKGBUILDDIR»/Tests/RunCMake/RunCMake.cmake:74 (message):
 CommandComments - FAILED:

 Result is [1], not [0].

 Actual stdout:

  actual-out> -- Configuring incomplete, errors occurred!

 Actual stderr:

  actual-err> CMake Error at /«PKGBUILDDIR»/Modules/CMakeDetermineSystem.cmake:170 (file):
  actual-err>   file Internal CMake error when trying to open file:
  actual-err>   //CMakeFiles/CMakeOutput.log for writing.
  actual-err> Call Stack (most recent call first):
  actual-err>   CMakeLists.txt:2 (project)
  actual-err> 
  actual-err> 
  actual-err> CMake Error: Could not open file for write in copy operation //CMakeFiles/2.8.12.1/CMakeSystem.cmake.tmp
  actual-err> CMake Error: : System Error: No such file or directory
  actual-err> CMake Error at /«PKGBUILDDIR»/Modules/CMakeDetermineSystem.cmake:182 (configure_file):
  actual-err>   configure_file Problem configuring file
  actual-err> Call Stack (most recent call first):
  actual-err>   CMakeLists.txt:2 (project)
  actual-err> 
  actual-err> 
  actual-err> Example Message
  actual-err> Example Message
  actual-err> Example Message
  actual-err> Second Line of Example
  actual-err> CMake Error: Cannot open file for write: //CMakeCache.txt.tmp
  actual-err> CMake Error: : System Error: Permission denied
  actual-err> CMake Error: Unable to open cache file for save. //CMakeCache.txt
  actual-err> CMake Error: : System Error: Permission denied

Call Stack (most recent call first):
 /«PKGBUILDDIR»/Tests/RunCMake/Syntax/RunCMakeTest.cmake:6 (run_cmake)



       Start 247: RunCMake.add_dependencies
240/307 Test #247: RunCMake.add_dependencies ........................   Passed    0.41 sec


<--snip-->

Total Test time (real) = 177.15 sec

The following tests FAILED:
	246 - RunCMake.Syntax (Failed)
Errors while running CTest
Makefile:136: recipe for target 'test' failed
make[2]: *** [test] Error 8


Previous versions suceeded and the changelog doesn't indicate any 
relavent changes so IMO this is most likely either a glitch or a change 
elsewhere in the system.

If anyone with debian-ports wanna-build access is reading this then a 
requeue would be appreciated so we can see if this was a one-off glitch 
or something more serious.

I tried doing a test build locally using user mode qemu but it hung at

-- Performing Test QT4_WORKS
-- Performing Test QT4_WORKS - Success
-- Performing Test run_pic_test
-- Performing Test run_pic_test - Success