posix: relocate Kconfig.eventfd to Kconfig.compat

While event file descriptors (eventfd) are extremely useful, the
API has still not been formalized as part of the POSIX
specification.

Therefore, move this to a separate Kconfig menu for "compat"
(compatibility) features.

Signed-off-by: Chris Friedt <cfriedt@tenstorrent.com>

lib/posix/options/Kconfig

@@ -35,6 +35,8 @@ rsource "Kconfig.sync_io"
 rsource "Kconfig.timer"
 rsource "Kconfig.xsi"
 
+rsource "Kconfig.compat"
+
 rsource "Kconfig.deprecated"
 
 endmenu # "POSIX Options"

lib/posix/options/Kconfig.compat

@@ -3,6 +3,8 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
+menu "Miscellaneous POSIX-related options"
+
 menuconfig EVENTFD
 	bool "Support for eventfd"
 	depends on !NATIVE_APPLICATION
@@ -14,10 +16,15 @@ menuconfig EVENTFD
 	  be used as an event wait/notify mechanism together with POSIX calls
 	  like read, write and poll.
 
+if EVENTFD
+
 config EVENTFD_MAX
 	int "Maximum number of eventfd's"
-	depends on EVENTFD
 	default 1
 	range 1 4096
 	help
 	  The maximum number of supported event file descriptors.
+
+endif # EVENTFD
+
+endmenu