tests: posix: single_process: ensure sysconf test passes

Ensure that the sysconf test passes with

CONFIG_POSIX_API=y
CONFIG_POSIX_AEP_CHOICE_PSE51=y
CONFIG_POSIX_SINGLE_PROCESS=y

A posix feature that definitely has not been implemented yet in Zephyr
needed to be chosen in order to ensure that the sysconf test would
return an error predictably.

Currently the _POSIX_THREAD_SPORADIC_SERVER feature fits that
description.

Signed-off-by: Chris Friedt <[email protected]>

Author: cfriedt

tests/posix/single_process/prj.conf

@@ -1,4 +1,6 @@
 CONFIG_ZTEST=y
+CONFIG_POSIX_API=y
+CONFIG_POSIX_AEP_CHOICE_PSE51=y
 CONFIG_POSIX_SINGLE_PROCESS=y
 
 # Let's explicitly choose PICOLIBC, so it is used if supported even if it would not have been the

tests/posix/single_process/src/sysconf.c

@@ -18,7 +18,7 @@ ZTEST(posix_single_process, test_posix_sysconf)
 	zassert_equal(ret, _POSIX_VERSION, "sysconf returned unexpected value %d", ret);
 
 	/* SC that's not implemented */
-	ret = sysconf(_SC_MEMLOCK_RANGE);
+	ret = sysconf(_SC_THREAD_SPORADIC_SERVER);
 	zassert_equal(ret, -1, "sysconf returned unexpected value %d", ret);
 
 	/* SC that value depends on target's configuration */