[glib] Fix dir separator in the Autotools build on Windows

[Emmanuele Bassi <ebassi src gnome org>]

commit c685ce973d5817ae36b430176f9ea7cb01c6726b
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Tue Jan 16 15:19:41 2018 +0000

    Fix dir separator in the Autotools build on Windows
    
    Just like we fixed the Meson build in commit f25c7a2a, we need to escape
    twice: once for the shell expansion, and the other for the C string
    constant.

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index ec20660..b4ec52e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -127,7 +127,7 @@ case "$host" in
     glib_pid_type='void *'
     glib_pid_format='p'
     glib_pollfd_format='%#x'
-    glib_dir_separator='\\'
+    glib_dir_separator='\\\\'
     glib_searchpath_separator=';'
     glib_cv_stack_grows=no
     # Unfortunately the mingw implementations of C99-style snprintf and vsnprintf