configure: commit test files

These are currently auto-generated, but meson needs the same files, so
lets commit them to reduce duplication.

v3: - Rename .build to build-support

Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dylan Baker <dylanx.c.baker@intel.com>

build-support/conftest.dyn

@@ -0,0 +1,3 @@
+{
+	radeon_drm_winsys_create;
+};

build-support/conftest.map

@@ -0,0 +1,6 @@
+VERSION_1 {
+    global:
+        main;
+    local:
+        *;
+};