Remove dependency on unzip.

Use tar instead which should be available on default Unixes and Windows

lua/nvim-treesitter/install.lua

@@ -37,6 +37,30 @@ local function get_revision(lang)
   return (lockfile[lang] and lockfile[lang].revision)
 end
 
+local function select_mkdir_cmd(directory, cwd, info_msg)
+  if fn.has('win32') == 1 then
+    return {
+      cmd = 'cmd',
+      opts = {
+        args = { '/C', 'mkdir', directory},
+	cwd = cwd,
+      },
+      info = info_msg,
+      err = "Could not create "..directory,
+    }
+  else
+    return {
+      cmd = 'mkdir',
+      opts = {
+        args = { directory },
+	cwd = cwd,
+      },
+      info = info_msg,
+      err = "Could not create "..directory,
+    }
+  end
+end
+
 local function select_rm_file_cmd(file, info_msg)
   if fn.has('win32') == 1 then
     return {
@@ -182,7 +206,7 @@ local function select_mv_cmd(from, to, cwd)
 end
 
 local function select_download_commands(repo, project_name, cache_folder, revision)
-  if vim.fn.executable('unzip') == 1 and vim.fn.executable('curl') == 1 and repo.url:find("github.com", 1, true) then
+  if vim.fn.executable('tar') == 1 and vim.fn.executable('curl') == 1 and repo.url:find("github.com", 1, true) then
 
     revision = revision or repo.branch or "master"
     local path_sep = utils.get_path_sep()
@@ -195,28 +219,29 @@ local function select_download_commands(repo, project_name, cache_folder, revisi
         opts = {
           args = {
             '-L', -- follow redirects
-            repo.url.."/archive/"..revision..".zip",
+            repo.url.."/archive/"..revision..".tar.gz",
             '--output',
-            project_name..".zip"
+            project_name..".tar.gz"
           },
           cwd = cache_folder,
         },
       },
+      select_mkdir_cmd(project_name..'-tmp', cache_folder, 'Creating temporary directory'),
       {
-        cmd = 'unzip',
+        cmd = 'tar',
         info = 'Extracting...',
-        err = 'Error during unzipping',
+        err = 'Error during tarball extraction.',
         opts = {
           args = {
-            '-o',
+            '-xvf',
-            project_name..".zip",
+            project_name..".tar.gz",
-            '-d',
+            '-C',
             project_name..'-tmp',
           },
           cwd = cache_folder,
         },
       },
-      select_rm_file_cmd(cache_folder..path_sep..project_name..".zip"),
+      select_rm_file_cmd(cache_folder..path_sep..project_name..".tar.gz"),
       select_mv_cmd(utils.join_path(project_name..'-tmp', repo.url:match('[^/]-$')..'-'..revision),
                     project_name,
                     cache_folder),