boilerplate: Cleanup the list of backends upon shutdown.

boilerplate/cairo-boilerplate.c

@@ -836,3 +836,16 @@ cairo_boilerplate_version_string (void)
 {
     return CAIRO_VERSION_STRING;
 }
+
+void
+cairo_boilerplate_fini (void)
+{
+    while (cairo_boilerplate_targets != NULL) {
+	struct cairo_boilerplate_target_list *next;
+
+	next = cairo_boilerplate_targets->next;
+
+	free (cairo_boilerplate_targets);
+	cairo_boilerplate_targets = next;
+    }
+}

boilerplate/cairo-boilerplate.h

@@ -216,6 +216,9 @@ cairo_boilerplate_version (void);
 const char*
 cairo_boilerplate_version_string (void);
 
+void
+cairo_boilerplate_fini (void);
+
 #include "cairo-boilerplate-system.h"
 
 CAIRO_END_DECLS

perf/cairo-perf-micro.c

@@ -476,6 +476,8 @@ static void
 cairo_perf_fini (cairo_perf_t *perf)
 {
     cairo_boilerplate_free_targets (perf->targets);
+    cairo_boilerplate_fini ();
+
     free (perf->times);
     cairo_debug_reset_static_data ();
 #if HAVE_FCFINI

perf/cairo-perf-trace.c

@@ -693,6 +693,8 @@ static void
 cairo_perf_fini (cairo_perf_t *perf)
 {
     cairo_boilerplate_free_targets (perf->targets);
+    cairo_boilerplate_fini ();
+
     free (perf->times);
     cairo_debug_reset_static_data ();
 #if HAVE_FCFINI

test/cairo-test.c

@@ -256,6 +256,8 @@ cairo_test_fini (cairo_test_context_t *ctx)
     if (ctx->own_targets)
 	cairo_boilerplate_free_targets (ctx->targets_to_test);
 
+    cairo_boilerplate_fini ();
+
     cairo_debug_reset_static_data ();
 #if HAVE_FCFINI
     FcFini ();