Reinstate g:solarized_use16.

Neovim ignores `&t_Co` and `&term`, so it is not possible in Neovim to
use the ANSI colors when `termguicolors` is not set.

Re-add this option to override the value of `s:t_Co`.

Fixes https://github.com/lifepillar/vim-solarized8/issues/71.

Readme.md

@@ -48,9 +48,10 @@ you have two possibilities:
    effect).
 
 2. Set your terminal's 16 ANSI colors (the colors in the range 0–15) to the
-   Solarized palette and `set t_Co=16` in Vim. Be aware that, if you set `t_Co`,
-   but your terminal does not use the Solarized palette, your colors will be
-   completely off.
+   Solarized palette and `set t_Co=16` in Vim (or `let g:solarized_use16=1`). Be
+   aware that, if you force the usage of your terminal colors, but your terminal
+   is not configured with the Solarized palette, your colors will be completely
+   off.
 
 Finally, if your terminal does not support true colors, you must *not* set
 `termguicolors`.
@@ -131,6 +132,7 @@ The following options were not available in the original Solarized:
   Solarized's cursor style (default: `0`). By default, the cursor is orange/red
   in light themes, and blue in dark themes (but please note that your terminal
   may override the cursor's color).
+- `g:solarized_use16`: set to `1` to force using your 16 ANSI terminal colors.
 - `g:solarized_extra_hi_groups`: set to `1` to enable Solarized
   filetype-specific syntax highlighting groups (default is `0`). Please be aware
   that there is [a long standing issue](https://github.com/vim/vim/issues/4405)

templates/_global.colortemplate

@@ -1,4 +1,5 @@
 # vim: ft=colortemplate fdm=marker
+#let s:t_Co = get(g:, '@optionprefix_use16', 0) ? 16 : s:t_Co
 #let s:italics = s:italics && get(g:, '@optionprefix_italics', 1)
 #let s:termtrans = get(g:, '@optionprefix_termtrans', 0) && !has('gui_running')
 Include: _linked_groups.colortemplate

templates/_help.colortemplate

@@ -23,6 +23,15 @@ Set to 1 to enable filetype-specific syntax highlight group.
 NOTE: setting this to 1 may leave "a wake of destruction when switching away"
 (T. Pope), that is, when you switch to a different colorscheme the
 highlighting may look wrong or disabled.
+						*g:@optionprefix_italics*
+Set to 0 if you do not want to enable italics. Note that the color scheme in
+normal circumstances automatically detects whether italics is available. You
+should never need to set this option explicitly. You may want to unset it if
+you do not want Vim to display italics even when the feature is available
+(e.g., in GUI versions of Vim).
+>
+	let g:@optionprefix_italics = 1
+<
 
 						*g:@optionprefix_old_cursor_style*
 Set to 1 if you want to use the original Solarized's cursor style. By default,
@@ -37,21 +46,17 @@ in the flat variant (of course, `"flat"` does not have any effect in the flat
 variant).
 >
 	let g:@optionprefix_statusline = "normal"
-<
-						*g:@optionprefix_italics*
-Set to 0 if you do not want to enable italics. Note that the color scheme in
-normal circumstances automatically detects whether italics is available. You
-should never need to set this option explicitly. You may want to unset it if
-you do not want Vim to display italics even when the feature is available
-(e.g., in GUI versions of Vim).
->
-	let g:@optionprefix_italics = 1
 <
 						*g:@optionprefix_termtrans*
 Set to 1 if you want a transparent background. Takes effect only in the
 terminal.
 >
 	let g:@optionprefix_termtrans = 0
+<
+						*g:@optionprefix_use16*
+Set to 1 if you want to force using the 16 ANSI terminal colors.
+>
+	let g:@optionprefix_use16 = 0
 <
 						*g:@optionprefix_visibility*
 Tweak the visibility of a few  elements. Allowed values are `"normal"`

templates/solarized8.colortemplate

@@ -9,10 +9,7 @@ Include:        _info.colortemplate
 Include: _help.colortemplate
 # }}}
 
-#let s:italics = s:italics && get(g:, '@optionprefix_italics', 1)
-#let s:termtrans = get(g:, '@optionprefix_termtrans', 0) && !has('gui_running')
-
-Include: _linked_groups.colortemplate
+Include: _global.colortemplate
 
 Variant: gui 256 16