test: skip arc4random on glibc

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

test/stdlib/Makefile.in

@@ -7,9 +7,12 @@ DODIFF_teston_exit := 1
 DODIFF_teststrtol  := 1
 
 TESTS_DISABLED :=
+GLIBC_TESTS_DISABLED :=
 ifeq ($(UCLIBC_HAS_PTY),)
 TESTS_DISABLED += ptytest
 endif
 ifeq ($(UCLIBC_HAS_ARC4RANDOM),)
 TESTS_DISABLED += testarc4random
+else
+GLIBC_TESTS_DISABLED += testarc4random
 endif