bindings: cxx: examples: add missing include

This patch adds proper include file to fix FTBFS issue in
gpiod_cxx_tests.cpp, please see below error.

gpiod_cxx_tests.cpp:29:19: note: 'std::function' is defined in header '<functional>'; did you forget to '#include <functional>'?
gpiod_cxx_tests.cpp:26:1:
+#include <functional>

Signed-off-by: SZ Lin (林上智) <sz.lin@moxa.com>
[Bartosz: tweaked the commit message]
Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>

diff --git a/bindings/cxx/examples/gpiod_cxx_tests.cpp b/bindings/cxx/examples/gpiod_cxx_tests.cpp
index df4820b3d96ed6dc1d2d761ca608f192b14f8410..767fe989bf9733cc7489987f3e4147b07775bae7 100644 (file)
--- a/bindings/cxx/examples/gpiod_cxx_tests.cpp
+++ b/bindings/cxx/examples/gpiod_cxx_tests.cpp
@@ -21,6 +21,7 @@
 #include <map>
 #include <cstring>
 #include <cerrno>
+#include <functional>
 
 #include <poll.h>