test: disable posix_fallocate64 for small embedded systems

Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>

test/unistd/Makefile.in

@@ -25,6 +25,8 @@ else
 # reordering is not supported, behaves as if POSIXLY_CORRECT would be set
 OPTS_tstgetopt   := -a -b -cfoobar --required foobar --optional=bazbug --none --colou --color --colour random
 endif
+# for embedded systems 4 GB disk space is not available
+TESTS_DISABLED += tst-posix_fallocate64
 
 # getconf.c lives in utils/
 # Testsuite cannot currently be built with O= anyway, so hardcode path here