diff --git a/CMakeLists.txt b/CMakeLists.txt
index ed9cb1f..e4cf7ec 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -121,6 +121,11 @@ if(HAVE_STRSEP)
 	add_definitions(-DHAVE_STRSEP)
 endif()
 
+check_function_exists(timegm HAVE_TIMEGM)
+if(HAVE_TIMEGM)
+	add_definitions(-DHAVE_TIMEGM)
+endif()
+
 check_function_exists(arc4random_buf HAVE_ARC4RANDOM_BUF)
 if(HAVE_ARC4RANDOM_BUF)
 	add_definitions(-DHAVE_ARC4RANDOM_BUF)
diff --git a/crypto/CMakeLists.txt b/crypto/CMakeLists.txt
index 3326dd7..792041e 100644
--- a/crypto/CMakeLists.txt
+++ b/crypto/CMakeLists.txt
@@ -596,6 +596,10 @@ if(NOT HAVE_STRNDUP)
 	endif()
 endif()
 
+if(NOT HAVE_TIMEGM)
+	set(CRYPTO_SRC ${CRYPTO_SRC} compat/timegm.c)
+endif()
+
 if(NOT HAVE_EXPLICIT_BZERO)
 	if(CMAKE_HOST_WIN32)
 		set(CRYPTO_SRC ${CRYPTO_SRC} compat/explicit_bzero_win.c)