[sysprof/wip/chergert/sysprof-3] libsysprof: be NULL safe

[Christian Hergert <chergert src gnome org>]

commit 0fa0b7b720e11b964af812494e6d93a96a66f609
Author: Christian Hergert <chergert redhat com>
Date:   Tue May 28 20:10:56 2019 -0700

    libsysprof: be NULL safe

 src/libsysprof/sysprof-kernel-symbol.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/src/libsysprof/sysprof-kernel-symbol.c b/src/libsysprof/sysprof-kernel-symbol.c
index 98d5f7b..cdd14fb 100644
--- a/src/libsysprof/sysprof-kernel-symbol.c
+++ b/src/libsysprof/sysprof-kernel-symbol.c
@@ -174,6 +174,9 @@ sysprof_kernel_symbol_lookup (SysprofKernelSymbol   *symbols,
                               guint                  first,
                               guint                  last)
 {
+  if (symbols == NULL)
+    return NULL;
+
   if (address >= symbols [last].address)
     {
       return &symbols [last];