cmake: add an Utilities library

Create a cmake utilities library for functions or macros that will be
shared across CMake files. For now, just add a function to check the
availability of pthread_setname_np(3). This is in preparation of adding
support for thread names where we'll also check this from the top level
CMake file.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>

cmake/Utilities.cmake

@@ -0,0 +1,11 @@
+function(check_pthread_set_name HAS_PTHREAD)
+        include(CheckSymbolExists)
+        set(CMAKE_REQUIRED_LIBRARIES ${PTHREAD_LIBRARIES})
+        set(CMAKE_REQUIRED_DEFINITIONS -D_GNU_SOURCE)
+        set(TMP_FLAGS "${CMAKE_C_FLAGS}")
+        set(CMAKE_C_FLAGS "")
+        check_symbol_exists(pthread_setname_np "pthread.h" ${HAS_PTHREAD})
+        set(CMAKE_C_FLAGS "${TMP_FLAGS}")
+        set(CMAKE_REQUIRED_LIBRARIES)
+        set(CMAKE_REQUIRED_DEFINITIONS)
+endfunction()

iiod/CMakeLists.txt

@@ -1,15 +1,8 @@
 cmake_minimum_required(VERSION 3.10)
 project(iiod C)
 
-include(CheckSymbolExists)
-set(CMAKE_REQUIRED_LIBRARIES ${PTHREAD_LIBRARIES})
-set(CMAKE_REQUIRED_DEFINITIONS -D_GNU_SOURCE)
-set(TMP_FLAGS "${CMAKE_C_FLAGS}")
-set(CMAKE_C_FLAGS "")
-check_symbol_exists(pthread_setname_np "pthread.h" HAS_PTHREAD_SETNAME_NP)
-set(CMAKE_C_FLAGS "${TMP_FLAGS}")
-set(CMAKE_REQUIRED_LIBRARIES)
-set(CMAKE_REQUIRED_DEFINITIONS)
+include(${CMAKE_SOURCE_DIR}/cmake/Utilities.cmake)
+CHECK_PTHREAD_SET_NAME(HAS_PTHREAD_SETNAME_NP)
 
 add_executable(iiod
 	iiod.c interpreter.c responder.c rw.c thread-pool.c