runtime(misc): unset compiler in various ftplugins

just to foster best practices

closes: #15798

Signed-off-by: Konfekt <Konfekt@users.noreply.github.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/ftplugin/zig.vim

@@ -1,7 +1,7 @@
 " Vim filetype plugin file
 " Language:     Zig
 " Maintainer:   Mathias Lindgren <math.lindgren@gmail.com>
-" Last Change:  2024 May 21
+" Last Change:  2024 Oct 04
 " Based on:     https://github.com/ziglang/zig.vim
 
 if exists("b:did_ftplugin")
@@ -13,8 +13,6 @@ let b:did_ftplugin = 1
 let s:cpo_save = &cpo
 set cpo&vim
 
-compiler zig_build
-
 " Match Zig builtin fns
 setlocal iskeyword+=@-@
 setlocal formatoptions-=t formatoptions+=croql
@@ -47,6 +45,11 @@ if exists('g:zig_std_dir')
     let b:undo_ftplugin .= ' | setl pa<'
 endif
 
+if !exists('current_compiler')
+    compiler zig_build
+    let b:undo_ftplugin .= "| compiler make"
+endif
+
 let &cpo = s:cpo_save
 unlet s:cpo_save
 " vim: tabstop=8 shiftwidth=4 softtabstop=4 expandtab