MinGW on Linux uses lowercase include files, part 2

On Windows this doesn't matter since the filesystems are case-
insensitive, but building BoringSSL on Linux with MinGW has
case-sensitive filesystems.

Change-Id: I1a145ee8dbb74a9f82e23ac40e7b9d23e03ccffc
diff --git a/src/crypto/rand/windows.c b/src/crypto/rand/windows.c
index 7bfcb1d..1a0cb8b 100644
--- a/src/crypto/rand/windows.c
+++ b/src/crypto/rand/windows.c
@@ -27,7 +27,7 @@
  * "Community Additions" comment on MSDN here:
  * http://msdn.microsoft.com/en-us/library/windows/desktop/aa387694.aspx */
 #define SystemFunction036 NTAPI SystemFunction036
-#include <NTSecAPI.h>
+#include <ntsecapi.h>
 #undef SystemFunction036
 
 #pragma warning(pop)
diff --git a/src/crypto/thread_test.c b/src/crypto/thread_test.c
index cecda88..e028b1b 100644
--- a/src/crypto/thread_test.c
+++ b/src/crypto/thread_test.c
@@ -22,7 +22,7 @@
 #if defined(OPENSSL_WINDOWS)
 
 #pragma warning(push, 3)
-#include <Windows.h>
+#include <windows.h>
 #pragma warning(pop)
 
 typedef HANDLE thread_t;