[glib] build: Document the chmod-scripts configure command

[Emmanuele Bassi <ebassi src gnome org>]

commit c1d58dd7e0c3047289702b7dc63407b29e00b6f3
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Tue Jan 30 11:18:34 2018 +0000

    build: Document the chmod-scripts configure command
    
    The chmod of all the scripts we generate from a template via configure
    is necessary because configure will not preserve the bits of the
    template when generating a new file.
    
    There's no explanation for it, and you have to hunt it down the commit
    history. Since Meson does the right thing, we added the executable bit
    on the templates, but we cannot remove the AC_CONFIG_COMMANDS macro from
    the Autotools build without breaking it. Let's document this, to avoid
    nasty surprises.

 configure.ac |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index b4ec52e..2d9a4e8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3516,6 +3516,8 @@ tests/refcount/Makefile
 m4macros/Makefile
 ])
 
+# We need this command because the configure script will not preserve
+# the same attributes of the template files
 AC_CONFIG_COMMANDS([chmod-scripts],
 [chmod 0755 glib-zip
 chmod 0755 glib-gettextize