lib/Frontend/CompilerInstance.cpp: Suppress a "Comparision of unsigned and signed" warning on Cygwin gcc-4.3.4.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@141488 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/CompilerInstance.cpp b/lib/Frontend/CompilerInstance.cpp
index c413a42..5526487 100644
--- a/lib/Frontend/CompilerInstance.cpp
+++ b/lib/Frontend/CompilerInstance.cpp
@@ -925,7 +925,7 @@
 #if LLVM_ON_WIN32
            Interval < MaxSeconds * 1000
 #else
-           Interval.tv_sec < MaxSeconds
+           Interval.tv_sec < (time_t)MaxSeconds
 #endif
            );