Don't do strlen on ui->compdir if it is NULL.  Duh.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@3920 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/coregrind/m_debuginfo/dwarf.c b/coregrind/m_debuginfo/dwarf.c
index 714a278..3b89dbe 100644
--- a/coregrind/m_debuginfo/dwarf.c
+++ b/coregrind/m_debuginfo/dwarf.c
@@ -508,6 +508,8 @@
 
       if (*data != '/' 
           /* not an absolute path */
+          && ui->compdir != NULL
+          /* actually got something sensible for compdir */
           && VG_(strlen)(ui->compdir) + VG_(strlen)(data) + 5/*paranoia*/ < NBUF
           /* it's short enough to concatenate */) 
       {