updated to 7.4.972

updated to 7.4.972

7.4.948  can't build when the insert_expand feature is disabled
7.4.949  highlighting wrong for 'colorcolumn' with a fullwidth sign
7.4.950  v:errors is not initialized
7.4.951  sorting number strings does not work as expected
7.4.952  'lispwords' is tested in the old way
7.4.953  a test may create the .res file with a wrong name
7.4.954  when using Lua there may be a crash (issue #468)
7.4.955  Vim doesn't recognize .pl6 and .pod6 files
7.4.956  a few more file name extensions not recognized
7.4.957  test_tagcase fails when using another language than English
7.4.958  Vim checks if the directory "$TMPDIR" exists
7.4.959  when setting 'term' the clipboard ownership is lost
7.4.960  detecting every version of nmake is clumsy
7.4.961  test107 fails in some circunstances
7.4.962  cannot run the tests with gvim and individual new tests
7.4.963  test_listlbr_utf8 sometimes fails
7.4.964  test 87 doesn't work in a shadow directory
7.4.965  on FreeBSD /dev/fd/ files are special
7.4.966  configure doesn't work with a space in a path
7.4.967  cross compilation on MS-windows doesn't work well
7.4.968  test86 and test87 are flaky in Appveyor
7.4.969  compiler warnings on Windowx x64 build
7.4.970  rare crash in getvcol()
7.4.971  the asin() function can't be used
7.4.972  memory leak when there is an error in setting an option