add configure-time check for timespecsub

1 files changed, 5 insertions, 0 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1efe6bc..bcba254 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -237,6 +237,11 @@ if(HAVE_GETPAGESIZE)
         add_definitions(-DHAVE_GETPAGESIZE)
 endif()
 
+check_symbol_exists(timespecsub sys/time.h HAVE_TIMESPECSUB)
+if(HAVE_TIMESPECSUB)
+        add_definitions(-DHAVE_TIMESPECSUB)
+endif()
+
 check_function_exists(timingsafe_bcmp HAVE_TIMINGSAFE_BCMP)
 if(HAVE_TIMINGSAFE_BCMP)
         add_definitions(-DHAVE_TIMINGSAFE_BCMP)