[glib] tests: Work around a gdb bug in assert-msg-test

[Philip Withnall <pwithnall src gnome org>]

commit 82adf7b5da71f44322139f109a3a39455432a961
Author: Philip Withnall <withnall endlessm com>
Date:   Mon Nov 27 11:29:15 2017 +0000

    tests: Work around a gdb bug in assert-msg-test
    
    It seems that when GLib is compiled without CFLAGS=-g, gdb can’t work
    out the size of __glib_assert_msg, so assumes it’s 4 bytes — even on
    64-bit systems. This causes it to not read the most significant 4 bytes
    of the assertion message pointer, and hence it can’t print the stored
    assertion message. This causes assert-msg-test to fail.
    
    The upstream gdb bug is
    https://sourceware.org/bugzilla/show_bug.cgi?id=22501.
    
    Work around that by referencing and dereferencing __glib_assert_msg so
    that gdb treats it as a pointer of sizeof(char*) rather than of the size
    it incorrectly calculated from the library’s symbol table (or through
    some other mystical process).
    
    Signed-off-by: Philip Withnall <withnall endlessm com>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=782057

 tests/assert-msg-test.gdb |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/tests/assert-msg-test.gdb b/tests/assert-msg-test.gdb
index 63a2541..dbecaaf 100644
--- a/tests/assert-msg-test.gdb
+++ b/tests/assert-msg-test.gdb
@@ -1,4 +1,5 @@
 run
 set print elements 0
-print (char*) __glib_assert_msg
+# Work around https://sourceware.org/bugzilla/show_bug.cgi?id=22501
+print *((char**) &__glib_assert_msg)
 quit