diff --git a/include/CMakeLists.txt b/include/CMakeLists.txt
index 9d015cd5ea..59f5b62adc 100644
--- a/include/CMakeLists.txt
+++ b/include/CMakeLists.txt
@@ -38,5 +38,7 @@ elseif(HOST_SPARC64)
 	file(READ arch/sparc64/opensslconf.h OPENSSLCONF)
 elseif(HOST_X86_64)
 	file(READ arch/amd64/opensslconf.h OPENSSLCONF)
+else()
+	message(FATAL_ERROR "Architecture not supported")
 endif()
 file(WRITE ${CMAKE_BINARY_DIR}/include/openssl/opensslconf.h "${OPENSSLCONF}")