libglnx porting: Use glnx_set_error_from_errno

⚠️ There is a notable spiked pit trap here around
`posix_fallocate()` and `errno`.  This has bit other projects,
see e.g.
https://github.com/systemd/systemd/commit/7bb87460e691d30c1a7fd23a1a8240776957e05f

Otherwise the port was straightforward.

src/libostree/ostree-sysroot-deploy.c

@@ -112,17 +112,17 @@ dirfd_copy_attributes_and_xattrs (int            src_parent_dfd,
 
   if (fstat (src_dfd, &src_stbuf) != 0)
     {
-      gs_set_error_from_errno (error, errno);
+      glnx_set_error_from_errno (error);
       goto out;
     }
   if (fchown (dest_dfd, src_stbuf.st_uid, src_stbuf.st_gid) != 0)
     {
-      gs_set_error_from_errno (error, errno);
+      glnx_set_error_from_errno (error);
       goto out;
     }
   if (fchmod (dest_dfd, src_stbuf.st_mode) != 0)
     {
-      gs_set_error_from_errno (error, errno);
+      glnx_set_error_from_errno (error);
       goto out;
     }
 
@@ -150,7 +150,7 @@ copy_dir_recurse (int              src_parent_dfd,
   /* Create with mode 0700, we'll fchmod/fchown later */
   if (mkdirat (dest_parent_dfd, name, 0700) != 0)
     {
-      gs_set_error_from_errno (error, errno);
+      glnx_set_error_from_errno (error);
       goto out;
     }
 
@@ -164,7 +164,7 @@ copy_dir_recurse (int              src_parent_dfd,
   srcd = fdopendir (src_dfd);
   if (!srcd)
     {
-      gs_set_error_from_errno (error, errno);
+      glnx_set_error_from_errno (error);
       goto out;
     }
 
@@ -180,7 +180,7 @@ copy_dir_recurse (int              src_parent_dfd,
       if (fstatat (src_dfd, name, &child_stbuf,
                    AT_SYMLINK_NOFOLLOW) != 0)
         {
-          gs_set_error_from_errno (error, errno);
+          glnx_set_error_from_errno (error);
           goto out;
         }
 
@@ -262,7 +262,7 @@ ensure_directory_from_template (int                 orig_etc_fd,
         }
       else
         {
-          gs_set_error_from_errno (error, errno);
+          glnx_set_error_from_errno (error);
           g_prefix_error (error, "mkdirat: ");
           goto out;
         }
@@ -312,7 +312,7 @@ copy_modified_config_file (int                 orig_etc_fd,
 
   if (fstatat (modified_etc_fd, path, &modified_stbuf, AT_SYMLINK_NOFOLLOW) < 0)
     {
-      gs_set_error_from_errno (error, errno);
+      glnx_set_error_from_errno (error);
       g_prefix_error (error, "Failed to read modified config file '%s': ", path);
       goto out;
     }
@@ -330,7 +330,7 @@ copy_modified_config_file (int                 orig_etc_fd,
       dest_parent_dfd = dup (new_etc_fd);
       if (dest_parent_dfd == -1)
         {
-          gs_set_error_from_errno (error, errno);
+          glnx_set_error_from_errno (error);
           goto out;
         }
     }
@@ -343,7 +343,7 @@ copy_modified_config_file (int                 orig_etc_fd,
         ;
       else
         {
-          gs_set_error_from_errno (error, errno);
+          glnx_set_error_from_errno (error);
           goto out;
         }
     }
@@ -369,7 +369,7 @@ copy_modified_config_file (int                 orig_etc_fd,
     {
       if (unlinkat (new_etc_fd, path, 0) < 0)
         {
-          gs_set_error_from_errno (error, errno);
+          glnx_set_error_from_errno (error);
           goto out;
         }
     }
@@ -1367,7 +1367,7 @@ install_deployment_kernel (OstreeSysroot   *sysroot,
     {
       if (errno != ENOENT)
         {
-          gs_set_error_from_errno (error, errno);
+          glnx_set_error_from_errno (error);
           goto out;
         }
       else