[sigzero]

Patch 7.4.1770

  Problem:    Cannot use true color in the terminal.
  Solution:   Add the 'guicolors' option. (Nikolai Pavlov)
  Files:      runtime/doc/options.txt, runtime/doc/term.txt,
            runtime/doc/various.txt, src/auto/configure, src/config.h.in,
            src/configure.in, src/eval.c, src/globals.h, src/hardcopy.c,
            src/option.c, src/option.h, src/proto/term.pro, src/screen.c,
            src/structs.h, src/syntax.c, src/term.c, src/term.h,
            src/version.c, src/vim.h