eventfd: bring config to top-level of posix dir, since it is not posix

The eventfd configuration does not need to be so deeply nested within
POSIX since it does not depend on POSIX completely.

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

Author: cfriedt

lib/posix/CMakeLists.txt

@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
 
 add_subdirectory(options)
+add_subdirectory_ifdef(CONFIG_EVENTFD eventfd)
 add_subdirectory_ifdef(CONFIG_POSIX_SHELL shell)

lib/posix/Kconfig

@@ -7,4 +7,7 @@ menu "POSIX API Support"
 rsource "options/Kconfig"
 rsource "shell/Kconfig"
 
-endmenu # "POSIX API Support"
+endmenu
+
+# Eventfd Support (not officially POSIX)
+rsource "eventfd/Kconfig"

lib/posix/eventfd/CMakeLists.txt

@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_library()
+zephyr_library_sources(eventfd.c)

lib/posix/options/Kconfig.compat renamed to lib/posix/eventfd/Kconfig

@@ -3,8 +3,6 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-menu "Miscellaneous POSIX-related options"
-
 config EVENTFD
 	bool "Support for eventfd"
 	depends on !NATIVE_APPLICATION
@@ -14,5 +12,3 @@ config EVENTFD
 	  Enable support for event file descriptors, eventfd. An eventfd can
 	  be used as an event wait/notify mechanism together with POSIX calls
 	  like read, write and poll.
-
-endmenu

lib/posix/options/eventfd.c renamed to lib/posix/eventfd/eventfd.c

@@ -25,7 +25,7 @@ if (NOT CONFIG_TC_PROVIDES_POSIX_SIGNALS)
 endif()
 
 if(CONFIG_POSIX_API OR CONFIG_POSIX_THREADS OR CONFIG_POSIX_TIMERS OR
-  CONFIG_POSIX_MESSAGE_PASSING OR CONFIG_POSIX_FILE_SYSTEM OR CONFIG_EVENTFD OR
+  CONFIG_POSIX_MESSAGE_PASSING OR CONFIG_POSIX_FILE_SYSTEM OR
   CONFIG_POSIX_C_LIB_EXT OR CONFIG_POSIX_SINGLE_PROCESS)
   # This is a temporary workaround so that Newlib declares the appropriate
   # types for us. POSIX features to be formalized as part of #51211
@@ -34,7 +34,6 @@ if(CONFIG_POSIX_API OR CONFIG_POSIX_THREADS OR CONFIG_POSIX_TIMERS OR
 endif()
 
 zephyr_library()
-zephyr_library_sources_ifdef(CONFIG_EVENTFD eventfd.c)
 
 if (NOT CONFIG_TC_PROVIDES_POSIX_ASYNCHRONOUS_IO)
   zephyr_library_sources_ifdef(CONFIG_POSIX_ASYNCHRONOUS_IO aio.c)