i386: Add hidden weak undefined tests

* testsuite/ld-i386/i386.exp: Run weakundef1 tests.
	* testsuite/ld-i386/weakundef1.c: New file.

ld/ChangeLog

@@ -1,3 +1,8 @@
+2017-06-22  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* testsuite/ld-i386/i386.exp: Run weakundef1 tests.
+	* testsuite/ld-i386/weakundef1.c: New file.
+
 2017-06-22  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR ld/21090

ld/testsuite/ld-i386/i386.exp

@@ -1235,6 +1235,32 @@ if { [isnative]
     }
 }
 
+# Must be native with the C compiler.
+if { [isnative]
+     && [istarget "i?86-*-*"]
+     && [which $CC] != 0 } {
+    run_ld_link_exec_tests [list \
+	[list \
+	    "Run weakundef1 without PIE" \
+	    "$NOPIE_LDFLAGS" \
+	    "" \
+	    { weakundef1.c } \
+	    "weakundef1pie" \
+	    "pass.out" \
+	    "$NOPIE_CFLAGS" \
+	] \
+	[list \
+	    "Run weakundef1 with PIE" \
+	    "-pie" \
+	    "" \
+	    { weakundef1.c } \
+	    "weakundef1pie" \
+	    "pass.out" \
+	    "-fPIE" \
+	] \
+    ]
+}
+
 if { !([istarget "i?86-*-linux*"]
        || [istarget "x86_64-*-linux*"]) } {
     return

ld/testsuite/ld-i386/weakundef1.c

@@ -0,0 +1,16 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+extern int visibility_var_weak
+  __attribute__ ((weak, visibility ("hidden")));
+
+int
+main ()
+{
+  if (&visibility_var_weak != NULL)
+    abort ();
+
+  printf ("PASS\n");
+
+  return 0;
+}