Binary (FreeBSD): use system libelf

There are pkg elfutils. However it is not ABI compatible with system
libelf

CMakeLists.txt

@@ -69,7 +69,7 @@ cmake_dependent_option(ENABLE_FREETYPE "Enable freetype" ON "ANDROID" OFF)
 cmake_dependent_option(ENABLE_PULSE "Enable pulse" ON "LINUX OR SunOS" OFF)
 cmake_dependent_option(ENABLE_DDCUTIL "Enable ddcutil" ON "LINUX" OFF)
 cmake_dependent_option(ENABLE_DIRECTX_HEADERS "Enable DirectX headers for WSL" ON "LINUX" OFF)
-cmake_dependent_option(ENABLE_ELF "Enable libelf" ON "LINUX OR FreeBSD OR ANDROID" OFF)
+cmake_dependent_option(ENABLE_ELF "Enable libelf" ON "LINUX OR ANDROID" OFF)
 cmake_dependent_option(ENABLE_THREADS "Enable multithreading" ON "Threads_FOUND" OFF)
 cmake_dependent_option(ENABLE_LIBZFS "Enable libzfs" ON "LINUX OR FreeBSD OR SunOS" OFF)
 

src/common/init.c

@@ -242,7 +242,7 @@ void ffListFeatures(void)
         #if FF_HAVE_DDCUTIL
             "libddcutil\n"
         #endif
-        #if FF_HAVE_ELF
+        #if FF_HAVE_ELF || __sun || __FreeBSD__
             "libelf\n"
         #endif
         #if FF_HAVE_LIBZFS

src/util/binary_linux.c

@@ -1,11 +1,12 @@
 #include "binary.h"
 
-#if defined(FF_HAVE_ELF) || defined(__sun)
+#if defined(FF_HAVE_ELF) || defined(__sun) || defined(__FreeBSD__)
 
 #include "common/io/io.h"
 #include "common/library.h"
 #include "util/stringUtils.h"
 
+// WARNING: On FreeBSD, there are system `/usr/include/libelf.h` and pkg elfutils `/usr/local/include/libelf.h`; they are not compatible.
 #include <libelf.h>
 #include <fcntl.h>