cmake: Fix --check-build-system argument count check (#14784)

This internal option requires two arguments, not just one.  Fix the
argument count required to recognize the option.
Merge topic 'fix-check-build-system-crash' into next

3504f9b9 cmake: Fix --check-build-system argument count check (#14784)
KWSys 2014-03-03 (b1916e0a)

Extract upstream KWSys using the following shell commands.

$ git archive --prefix=upstream-kwsys/ b1916e0a | tar x
$ git shortlog --no-merges --abbrev=8 --format='%h %s' 606d7d6f..b1916e0a
Adrien Destugues (1):
      b1916e0a SystemInformation: Update CPU count code for Haiku

Clinton Stimpson (3):
      0d8ef429 Encoding:  Help enforce the use of wide apis on Windows.
      cfbc1cc8 FStream: Remove unused basic_filebuf declaration.
      b3b20cc0 FStream: Add ability to detect BOM.

Jiri Malak (1):
      e66d99b8 SystemTools: Fix compilation with Open Watcom

Matt McCormick (1):
      b3db597b SystemInformation: Mark EXECINFO_LIB as advanced

Change-Id: I154a92be7a3ec4c7c12bffbfcd7b50ec7de53c5f
Merge branch 'upstream-kwsys' into update-kwsys
Merge topic 'update-kwsys' into next

7db95df3 Merge branch 'upstream-kwsys' into update-kwsys
f096786d KWSys 2014-03-03 (b1916e0a)