Add missing <time.h> include.

Fixes build on FreeBSD 11.

--
PiperOrigin-RevId: 141029578
MOS_MIGRATED_REVID=141029578

src/main/cpp/util/file_platform.h

diff --git a/src/main/cpp/util/file_platform.h b/src/main/cpp/util/file_platform.h
index 58755f27..17c7e2e 100644
--- a/src/main/cpp/util/file_platform.h
+++ b/src/main/cpp/util/file_platform.h
@@ -16,6 +16,7 @@
 #define BAZEL_SRC_MAIN_CPP_UTIL_FILE_PLATFORM_H_
 
 #include <stdint.h>
+#include <time.h>
 
 #include <string>