[libFuzzer] [Windows] Include windows.h and psapi.h with lowercase

This fixes building on a case sensitive filesystem with mingw-w64
headers, where all headers are lowercase, and matches how these
headers are included elsewhere in compiler-rt.

Also include these headers with angle brackets, as they are system
headers.

Differential Revision: https://reviews.llvm.org/D51913

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk/lib/fuzzer@341983 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/FuzzerExtFunctionsDlsymWin.cpp b/FuzzerExtFunctionsDlsymWin.cpp
index 321b3ec..e09da3f 100644
--- a/FuzzerExtFunctionsDlsymWin.cpp
+++ b/FuzzerExtFunctionsDlsymWin.cpp
@@ -13,10 +13,10 @@
 
 #include "FuzzerExtFunctions.h"
 #include "FuzzerIO.h"
-#include "Windows.h"
+#include <windows.h>
 
 // This must be included after Windows.h.
-#include "Psapi.h"
+#include <psapi.h>
 
 namespace fuzzer {
 
diff --git a/FuzzerUtilWindows.cpp b/FuzzerUtilWindows.cpp
index 257723b..393b476 100644
--- a/FuzzerUtilWindows.cpp
+++ b/FuzzerUtilWindows.cpp
@@ -24,7 +24,7 @@
 #include <windows.h>
 
 // This must be included after windows.h.
-#include <Psapi.h>
+#include <psapi.h>
 
 namespace fuzzer {