From fe344be938fb5d4644553a6886f6455fa337ce72 Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Sun, 11 Aug 2013 19:21:03 +0200
Subject: Only link with librt when necessary

---
 CMakeLists.txt     | 21 ++++++++++++++++++++-
 src/CMakeLists.txt |  2 +-
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0fa9d72..9a98adb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -28,10 +28,11 @@ endif()
 
 include(CheckCSourceCompiles)
 include(CheckPrototypeDefinition)
+include(CheckSymbolExists)
 include(CheckTypeSize)
-set(CMAKE_EXTRA_INCLUDE_FILES "netinet/if_ether.h")
 set(CMAKE_REQUIRED_DEFINITIONS "-D_GNU_SOURCE")
 
+
 check_c_source_compiles("
 #include <sys/types.h>
 #include <sys/socket.h>
@@ -42,11 +43,29 @@ int main() {
 }
 " HAVE_AI_ADDRCONFIG)
 
+
 check_prototype_definition("get_current_dir_name" "char *get_current_dir_name(void)" "NULL" "unistd.h" HAVE_GET_CURRENT_DIR_NAME)
 
+
+set(RT_LIBRARY "")
+check_symbol_exists("clock_gettime" "time.h" HAVE_CLOCK_GETTIME)
+
+if(NOT HAVE_CLOCK_GETTIME)
+  set(RT_LIBRARY "rt")
+  list(append CMAKE_REQUIRED_LIBRARIES "rt")
+
+  check_symbol_exists("clock_gettime" "time.h" HAVE_CLOCK_GETTIME)
+  if(NOT HAVE_CLOCK_GETTIME)
+      message(FATAL_ERROR "clock_gettime() not found")
+  endif(NOT HAVE_CLOCK_GETTIME)
+endif(NOT HAVE_CLOCK_GETTIME)
+
+
+set(CMAKE_EXTRA_INCLUDE_FILES "netinet/if_ether.h")
 check_type_size("struct ethhdr" SIZEOF_ETHHDR)
 string(COMPARE NOTEQUAL "${SIZEOF_ETHHDR}" "" HAVE_ETHHDR)
 
+
 set(USE_BINDTODEVICE ${LINUX})
 set(USE_PMTU ${LINUX})
 set(USE_PKTINFO ${LINUX})
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index aed5b24..10e5656 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -39,7 +39,7 @@ add_executable(fastd
   ${METHODS}
 )
 set_target_properties(fastd PROPERTIES COMPILE_FLAGS -pthread ${UECC_CFLAGS_OTHER} COMPILE_DEFINITIONS _GNU_SOURCE LINK_FLAGS -pthread ${UECC_LDFLAGS_OTHER})
-target_link_libraries(fastd rt ${CAP_LIBRARY} ${UECC_LIBRARIES} ${NACL_LIBRARY})
+target_link_libraries(fastd ${RT_LIBRARY} ${CAP_LIBRARY} ${UECC_LIBRARIES} ${NACL_LIBRARY})
 
 add_custom_target(
     version
-- 
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