diff --git a/test/dl/test_base.rb b/test/dl/test_base.rb
index d7fb354b6d..6f13d7d5f6 100644
--- a/test/dl/test_base.rb
+++ b/test/dl/test_base.rb
@@ -33,8 +33,8 @@ when /bsd|dragonfly/
   libc_so = "/usr/lib/libc.so"
   libm_so = "/usr/lib/libm.so"
 else
-  libc_so = ARGV[0]
-  libm_so = ARGV[1]
+  libc_so = ARGV[0] if ARGV[0] && ARGV[0][0] == ?/
+  libm_so = ARGV[1] if ARGV[1] && ARGV[1][0] == ?/
   if( !(libc_so && libm_so) )
     $stderr.puts("libc and libm not found: #{$0} <libc> <libm>")
   end