From b65674a8e3d533dd0b51ef58e7f7779d85c799c9 Mon Sep 17 00:00:00 2001
From: Philippe Teuwen <yobibe@gmail.com>
Date: Thu, 2 Mar 2017 23:42:36 +0100
Subject: [PATCH] Some systems (e.g. glibc < 2.17) require librt to get
 clock_gettime -> CMAKE

---
 CMakeLists.txt        | 16 ++++++++++++++++
 libnfc/CMakeLists.txt |  4 ++++
 2 files changed, 20 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f5d1f7a..76babf2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -148,6 +148,22 @@ ENDIF(NOT WIN32)
 
 INCLUDE(LibnfcDrivers)
 
+IF(UNIX AND NOT APPLE)
+    IF(I2C_REQUIRED)
+        # Inspired from http://cmake.3232098.n2.nabble.com/RFC-cmake-analog-to-AC-SEARCH-LIBS-td7585423.html
+        INCLUDE (CheckFunctionExists)
+        INCLUDE (CheckLibraryExists)
+        CHECK_FUNCTION_EXISTS (clock_gettime HAVE_CLOCK_GETTIME)
+        IF (NOT HAVE_CLOCK_GETTIME)
+            CHECK_LIBRARY_EXISTS (rt clock_gettime "" HAVE_CLOCK_GETTIME_IN_RT)
+            IF (HAVE_CLOCK_GETTIME_IN_RT)
+                SET(LIBRT_FOUND TRUE)
+                SET(LIBRT_LIBRARIES "rt")
+            ENDIF (HAVE_CLOCK_GETTIME_IN_RT)
+        ENDIF (NOT HAVE_CLOCK_GETTIME)
+    ENDIF(I2C_REQUIRED)
+ENDIF(UNIX AND NOT APPLE)
+
 IF(PCSC_INCLUDE_DIRS)
   INCLUDE_DIRECTORIES(${PCSC_INCLUDE_DIRS})
   LINK_DIRECTORIES(${PCSC_LIBRARY_DIRS})
diff --git a/libnfc/CMakeLists.txt b/libnfc/CMakeLists.txt
index e69f614..79bab5d 100644
--- a/libnfc/CMakeLists.txt
+++ b/libnfc/CMakeLists.txt
@@ -79,6 +79,10 @@ IF(LIBUSB_FOUND)
   TARGET_LINK_LIBRARIES(nfc ${LIBUSB_LIBRARIES})
 ENDIF(LIBUSB_FOUND)
 
+IF(LIBRT_FOUND)
+  TARGET_LINK_LIBRARIES(nfc ${LIBRT_LIBRARIES})
+ENDIF(LIBRT_FOUND)
+
 SET_TARGET_PROPERTIES(nfc PROPERTIES SOVERSION 5 VERSION 5.0.1)
 
 IF(WIN32)