[gimp] libgimpwidgets: call babl_exit() when unloading

[N/A <ell src gnome org>]

commit e64e61ca582697849c852bc0332cb34be574a90a
Author: Ell <ell_se yahoo com>
Date:   Wed May 31 21:56:07 2017 -0400

    libgimpwidgets: call babl_exit() when unloading
    
    If the compiler supports destructors (which should cover at least
    GCC and Clang), pair the call to babl_init() in gimp_widgets_init()
    with a call to babl_exit() when the library in unloaded.  This is
    important in particular since the babl fish cache is constructed/
    updated upon the last matched call to babl_exit().

 configure.ac                         |    6 ++++++
 libgimpwidgets/gimpwidgets-private.c |   23 +++++++++++++++++++++--
 2 files changed, 27 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 214886c..360d2b0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -945,6 +945,12 @@ AC_CHECK_FUNC(rint, AC_DEFINE(HAVE_RINT, 1,
     AC_DEFINE(HAVE_RINT)])])
 
 
+##############################
+# Check for attributes we need
+##############################
+
+AX_GCC_FUNC_ATTRIBUTE(destructor)
+
 #####################################################################
 # Check for extra libs needed for getaddrinfo, getnameinfo and socket
 #####################################################################
diff --git a/libgimpwidgets/gimpwidgets-private.c b/libgimpwidgets/gimpwidgets-private.c
index c508be1..92fd9c2 100644
--- a/libgimpwidgets/gimpwidgets-private.c
+++ b/libgimpwidgets/gimpwidgets-private.c
@@ -34,6 +34,8 @@
 #include "libgimp/libgimp-intl.h"
 
 
+static gboolean       gimp_widgets_initialized  = FALSE;
+
 GimpHelpFunc          _gimp_standard_help_func  = NULL;
 GimpGetColorFunc      _gimp_get_foreground_func = NULL;
 GimpGetColorFunc      _gimp_get_background_func = NULL;
@@ -63,8 +65,6 @@ gimp_widgets_init (GimpHelpFunc          standard_help_func,
                    GimpGetColorFunc      get_background_func,
                    GimpEnsureModulesFunc ensure_modules_func)
 {
-  static gboolean  gimp_widgets_initialized = FALSE;
-
   g_return_if_fail (standard_help_func != NULL);
 
   if (gimp_widgets_initialized)
@@ -85,3 +85,22 @@ gimp_widgets_init (GimpHelpFunc          standard_help_func,
 
   gimp_widgets_initialized = TRUE;
 }
+
+/* clean up babl (in particular, so that the fish cache is constructed) if the
+ * compiler supports destructors
+ */
+#ifdef HAVE_FUNC_ATTRIBUTE_DESTRUCTOR
+
+__attribute__ ((destructor))
+static void
+gimp_widgets_exit (void)
+{
+  if (gimp_widgets_initialized)
+    babl_exit ();
+}
+
+#elif defined (__GNUC__)
+
+#warning babl_init() not paired with babl_exit()
+
+#endif