cmake: move functions to src/cmake

Change-Id: Ibcb7105fa7e3c09efdce01bccd4de235fe33ea99
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/src/cmake/memfd.cmake b/src/cmake/memfd.cmake
new file mode 100644
index 0000000..ca499c4
--- /dev/null
+++ b/src/cmake/memfd.cmake
@@ -0,0 +1,26 @@
+# Copyright (c) 2018 Cisco and/or its affiliates.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at:
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+##############################################################################
+# Check for memfd_create headers and libs
+##############################################################################
+check_c_source_compiles("
+  #define _GNU_SOURCE
+  #include <sys/mman.h>
+  int main() { return memfd_create (\"/dev/false\", 0); }
+" HAVE_MEMFD_CREATE)
+
+if (HAVE_MEMFD_CREATE)
+    add_definitions(-DHAVE_MEMFD_CREATE)
+endif()
+