posix: options: define _POSIX_TIMERS when configured

Define _POSIX_TIMERS=200809L when so configured.

This change is required to ensure that Newlib provides the necessary POSIX
timer API definitions in toolchain headers.

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

Author: cfriedt

include/zephyr/posix/posix_features.h

@@ -177,10 +177,6 @@
 #define _POSIX_TIMEOUTS _POSIX_VERSION
 #endif
 
-#ifdef CONFIG_POSIX_TIMERS
-#define _POSIX_TIMERS _POSIX_VERSION
-#endif
-
 /* #define _POSIX_TRACE (-1L) */
 /* #define _POSIX_TRACE_EVENT_FILTER (-1L) */
 /* #define _POSIX_TRACE_INHERIT (-1L) */

lib/posix/options/CMakeLists.txt

@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 
+set(POSIX_VERSION 200809L)
 set(GEN_DIR ${ZEPHYR_BINARY_DIR}/include/generated)
 
 zephyr_syscall_header_ifdef(CONFIG_POSIX_CLOCK_SELECTION posix_clock.h)
@@ -125,6 +126,9 @@ if (NOT CONFIG_TC_PROVIDES_POSIX_TIMERS)
     timespec_to_timeout.c
   )
 endif()
+if (CONFIG_POSIX_TIMERS)
+  zephyr_compile_definitions(-D_POSIX_TIMERS=${POSIX_VERSION})
+endif()
 
 if (NOT CONFIG_TC_PROVIDES_POSIX_READER_WRITER_LOCKS)
   # Note: the Option is _POSIX_READER_WRITER_LOCKS, while the Option Group is POSIX_RW_LOCKS.