cmake: fix `unseal` warning and add build to ignore

.gitignore

@@ -32,6 +32,9 @@ RemoteSystemsTempFiles
 IDE/IAR-EWARM/settings
 wolftpm/options.h
 
+# common cmake build location
+build/
+
 examples/wrap/wrap_test
 examples/native/native_test
 examples/bench/bench

examples/seal/unseal.c

@@ -28,6 +28,7 @@
 #include <examples/seal/seal.h>
 #include <examples/tpm_io.h>
 #include <examples/tpm_test.h>
+#include <examples/tpm_test_keys.h>
 
 #include <stdio.h>
 #include <stdlib.h> /* atoi */