diff --git a/Source/kwsys/CMakeLists.txt b/Source/kwsys/CMakeLists.txt
index 68e122e7d9..af172293ff 100644
--- a/Source/kwsys/CMakeLists.txt
+++ b/Source/kwsys/CMakeLists.txt
@@ -879,22 +879,25 @@ endif()
 
 # For building kwsys itself, we use a macro defined on the command
 # line to configure the namespace in the C and C++ source files.
-add_definitions("-DKWSYS_NAMESPACE=${KWSYS_NAMESPACE}")
+add_compile_definitions(KWSYS_NAMESPACE=${KWSYS_NAMESPACE})
 
 # Disable deprecation warnings for standard C functions.
 if(MSVC OR (WIN32 AND (CMAKE_C_COMPILER_ID STREQUAL "Intel" OR
    (CMAKE_C_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_SIMULATE_ID STREQUAL "MSVC"))))
-  add_definitions(
-    -D_CRT_NONSTDC_NO_DEPRECATE
-    -D_CRT_SECURE_NO_DEPRECATE
-    -D_CRT_SECURE_NO_WARNINGS
-    -D_SCL_SECURE_NO_DEPRECATE
+  add_compile_definitions(
+    _CRT_NONSTDC_NO_DEPRECATE
+    _CRT_SECURE_NO_DEPRECATE
+    _CRT_SECURE_NO_WARNINGS
+    _SCL_SECURE_NO_DEPRECATE
     )
 endif()
 
 if(WIN32)
   # Help enforce the use of wide Windows apis.
-  add_definitions(-DUNICODE -D_UNICODE)
+  add_compile_definitions(UNICODE _UNICODE)
+
+  # Minimize "windows.h".  We include granular Windows SDK headers as needed.
+  add_compile_definitions(WIN32_LEAN_AND_MEAN)
 endif()
 
 if(KWSYS_USE_String)
diff --git a/Source/kwsys/ProcessWin32.c b/Source/kwsys/ProcessWin32.c
index 07e19cdb2e..6e269638b5 100644
--- a/Source/kwsys/ProcessWin32.c
+++ b/Source/kwsys/ProcessWin32.c
@@ -30,6 +30,7 @@ a UNIX-style select system call.
 #endif
 #include <io.h>     /* _unlink */
 #include <stdio.h>  /* snprintf */
+#include <stdlib.h> /* malloc */
 #include <string.h> /* strlen, strdup */
 
 #ifndef _MAX_FNAME
diff --git a/Source/kwsys/SystemInformation.cxx b/Source/kwsys/SystemInformation.cxx
index 743c224437..96dff616cc 100644
--- a/Source/kwsys/SystemInformation.cxx
+++ b/Source/kwsys/SystemInformation.cxx
@@ -65,6 +65,7 @@
 using siginfo_t = int;
 #  endif
 #  include <powerbase.h>
+#  include <winternl.h> // NTSTATUS
 #else
 #  include <sys/types.h>
 
diff --git a/Source/kwsys/SystemTools.cxx b/Source/kwsys/SystemTools.cxx
index 0e64be4aa3..b260e38701 100644
--- a/Source/kwsys/SystemTools.cxx
+++ b/Source/kwsys/SystemTools.cxx
@@ -1345,7 +1345,7 @@ bool SystemTools::FileExists(std::string const& filename)
         return false;
       }
 
-      byte buffer[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
+      BYTE buffer[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
       DWORD bytesReturned = 0;
 
       if (!DeviceIoControl(handle, FSCTL_GET_REPARSE_POINT, nullptr, 0, buffer,
@@ -3091,7 +3091,7 @@ bool SystemTools::FileIsSymlinkWithAttr(std::wstring const& path,
       if (hFile == INVALID_HANDLE_VALUE) {
         return false;
       }
-      byte buffer[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
+      BYTE buffer[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
       DWORD bytesReturned = 0;
       if (!DeviceIoControl(hFile, FSCTL_GET_REPARSE_POINT, nullptr, 0, buffer,
                            MAXIMUM_REPARSE_DATA_BUFFER_SIZE, &bytesReturned,
@@ -3157,7 +3157,7 @@ Status SystemTools::ReadSymlink(std::string const& newName,
   if (hFile == INVALID_HANDLE_VALUE) {
     return Status::Windows_GetLastError();
   }
-  byte buffer[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
+  BYTE buffer[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
   DWORD bytesReturned = 0;
   Status status;
   if (!DeviceIoControl(hFile, FSCTL_GET_REPARSE_POINT, nullptr, 0, buffer,
diff --git a/Source/kwsys/testProcess.c b/Source/kwsys/testProcess.c
index 1ab746b7a1..4ce259f839 100644
--- a/Source/kwsys/testProcess.c
+++ b/Source/kwsys/testProcess.c
@@ -23,6 +23,8 @@
 
 #if defined(_WIN32)
 #  include <windows.h>
+
+#  include <shellapi.h>
 #else
 #  include <signal.h>
 #  include <unistd.h>