Index: cmake/LLDBDependencies.cmake
===================================================================
--- cmake/LLDBDependencies.cmake
+++ cmake/LLDBDependencies.cmake
@@ -91,8 +91,8 @@
 if ( CMAKE_SYSTEM_NAME MATCHES "Windows" )
   list(APPEND LLDB_USED_LIBS
     lldbPluginProcessWindowsCommon
-    Ws2_32
-    Rpcrt4
+    ws2_32
+    rpcrt4
     )
 endif ()
 
Index: cmake/modules/AddLLDB.cmake
===================================================================
--- cmake/modules/AddLLDB.cmake
+++ cmake/modules/AddLLDB.cmake
@@ -49,7 +49,7 @@
   endif()
 
   #PIC not needed on Win
-  if (NOT MSVC)
+  if (NOT WIN32)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fPIC")
   endif()
 
Index: cmake/modules/LLDBConfig.cmake
===================================================================
--- cmake/modules/LLDBConfig.cmake
+++ cmake/modules/LLDBConfig.cmake
@@ -242,8 +242,10 @@
 endif()
 
 # Use the Unicode (UTF-16) APIs by default on Win32
-if (CMAKE_SYSTEM_NAME MATCHES "Windows")
-	add_definitions( /D _UNICODE /D UNICODE )
+if (MSVC)
+    add_definitions( /D _UNICODE /D UNICODE )
+elseif (MINGW)
+    add_definitions( -D_UNICODE -DUNICODE )
 endif()
 
 set(LLDB_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
Index: include/lldb/Host/windows/windows.h
===================================================================
--- include/lldb/Host/windows/windows.h
+++ include/lldb/Host/windows/windows.h
@@ -11,9 +11,11 @@
 #define LLDB_lldb_windows_h_
 
 #define NTDDI_VERSION NTDDI_VISTA
+#undef _WIN32_WINNT // undef a previous definition to avoid warning
 #define _WIN32_WINNT _WIN32_WINNT_VISTA
 #define WIN32_LEAN_AND_MEAN
 #define NOGDI
+#undef NOMINMAX // undef a previous definition to avoid warning
 #define NOMINMAX
 #include <windows.h>
 #undef GetUserName
Index: source/API/SystemInitializerFull.cpp
===================================================================
--- source/API/SystemInitializerFull.cpp
+++ source/API/SystemInitializerFull.cpp
@@ -107,7 +107,7 @@
 #include "Plugins/Process/FreeBSD/ProcessFreeBSD.h"
 #endif
 
-#if defined(_MSC_VER)
+#if defined(_WIN32)
 #include "Plugins/Process/Windows/Common/ProcessWindows.h"
 #include "lldb/Host/windows/windows.h"
 #endif
@@ -332,7 +332,7 @@
   ObjCPlusPlusLanguage::Initialize();
   OCamlLanguage::Initialize();
 
-#if defined(_MSC_VER)
+#if defined(_WIN32)
   ProcessWindows::Initialize();
 #endif
 #if defined(__FreeBSD__)
Index: source/Core/Mangled.cpp
===================================================================
--- source/Core/Mangled.cpp
+++ source/Core/Mangled.cpp
@@ -9,9 +9,9 @@
 
 // FreeBSD9-STABLE requires this to know about size_t in cxxabi.h
 #include <cstddef>
-#if defined(_MSC_VER)
+#if defined(_WIN32)
 #include "lldb/Host/windows/windows.h"
-#include <Dbghelp.h>
+#include <dbghelp.h>
 #pragma comment(lib, "dbghelp.lib")
 #endif
 
Index: source/Host/common/File.cpp
===================================================================
--- source/Host/common/File.cpp
+++ source/Host/common/File.cpp
@@ -222,7 +222,7 @@
   }
 
   do {
-#ifdef _WIN32
+#ifdef _MSC_VER
     std::wstring wpath;
     if (!llvm::ConvertUTF8toWide(path, wpath)) {
       m_descriptor = -1;
Index: source/Host/windows/Host.cpp
===================================================================
--- source/Host/windows/Host.cpp
+++ source/Host/windows/Host.cpp
@@ -29,7 +29,7 @@
 #include "llvm/Support/ConvertUTF.h"
 
 // Windows includes
-#include <TlHelp32.h>
+#include <tlhelp32.h>
 
 using namespace lldb;
 using namespace lldb_private;
Index: source/Host/windows/HostProcessWindows.cpp
===================================================================
--- source/Host/windows/HostProcessWindows.cpp
+++ source/Host/windows/HostProcessWindows.cpp
@@ -16,7 +16,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/ConvertUTF.h"
 
-#include <Psapi.h>
+#include <psapi.h>
 
 using namespace lldb_private;
 
Index: source/Host/windows/ProcessRunLock.cpp
===================================================================
--- source/Host/windows/ProcessRunLock.cpp
+++ source/Host/windows/ProcessRunLock.cpp
@@ -10,16 +10,6 @@
 #include "lldb/Host/ProcessRunLock.h"
 #include "lldb/Host/windows/windows.h"
 
-namespace {
-#if defined(__MINGW32__)
-// Taken from WinNT.h
-typedef struct _RTL_SRWLOCK { PVOID Ptr; } RTL_SRWLOCK, *PRTL_SRWLOCK;
-
-// Taken from WinBase.h
-typedef RTL_SRWLOCK SRWLOCK, *PSRWLOCK;
-#endif
-}
-
 static PSRWLOCK GetLock(lldb::rwlock_t lock) {
   return static_cast<PSRWLOCK>(lock);
 }
Index: source/Plugins/ObjectFile/PECOFF/WindowsMiniDump.cpp
===================================================================
--- source/Plugins/ObjectFile/PECOFF/WindowsMiniDump.cpp
+++ source/Plugins/ObjectFile/PECOFF/WindowsMiniDump.cpp
@@ -16,7 +16,7 @@
 
 #ifdef _WIN32
 #include "lldb/Host/windows/windows.h"
-#include <DbgHelp.h> // for MiniDumpWriteDump
+#include <dbghelp.h> // for MiniDumpWriteDump
 #endif
 
 namespace lldb_private {
Index: source/Plugins/Process/Windows/Common/ExceptionRecord.h
===================================================================
--- source/Plugins/Process/Windows/Common/ExceptionRecord.h
+++ source/Plugins/Process/Windows/Common/ExceptionRecord.h
@@ -12,7 +12,7 @@
 
 #include "lldb/Host/windows/windows.h"
 #include "lldb/lldb-forward.h"
-#include <DbgHelp.h>
+#include <dbghelp.h>
 
 #include <memory>
 #include <vector>
Index: source/Target/ProcessLaunchInfo.cpp
===================================================================
--- source/Target/ProcessLaunchInfo.cpp
+++ source/Target/ProcessLaunchInfo.cpp
@@ -294,7 +294,7 @@
                       __FUNCTION__);
 
         int open_flags = O_RDWR | O_NOCTTY;
-#if !defined(_MSC_VER)
+#if !defined(_WIN32)
         // We really shouldn't be specifying platform specific flags
         // that are intended for a system call in generic code.  But
         // this will have to do for now.
Index: tools/driver/Driver.cpp
===================================================================
--- tools/driver/Driver.cpp
+++ tools/driver/Driver.cpp
@@ -1208,13 +1208,13 @@
 }
 
 int
-#ifdef WIN32
+#ifdef _MSC_VER
 wmain(int argc, wchar_t const *wargv[])
 #else
 main(int argc, char const *argv[])
 #endif
 {
-#ifdef _WIN32
+#ifdef _MSC_VER
   // Convert wide arguments to UTF-8
   std::vector<std::string> argvStrings(argc);
   std::vector<const char *> argvPointers(argc);
Index: tools/lldb-mi/MICmnStreamStdin.cpp
===================================================================
--- tools/lldb-mi/MICmnStreamStdin.cpp
+++ tools/lldb-mi/MICmnStreamStdin.cpp
@@ -9,7 +9,7 @@
 
 // Third Party Headers
 #ifdef _MSC_VER
-#include <Windows.h>
+#include <windows.h>
 #endif
 #include <string.h> // For std::strerror()
 
Index: tools/lldb-mi/MIUtilDebug.cpp
===================================================================
--- tools/lldb-mi/MIUtilDebug.cpp
+++ tools/lldb-mi/MIUtilDebug.cpp
@@ -9,7 +9,7 @@
 
 // Third party headers:
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #endif
 
 // In-house headers: