improve cmake windows debug configuration (fixes #77)
diff --git a/docs/cmake.rst b/docs/cmake.rst
index e8cfa61..eb1f885 100644
--- a/docs/cmake.rst
+++ b/docs/cmake.rst
@@ -84,12 +84,17 @@
 
     if (WIN32)
       if (MSVC)
-        # Enforce size-based optimization and link time code generation
-        # on MSVC (~30% smaller binaries in experiments). /bigobj is needed
-        # for bigger binding projects due to the limit to 64k addressable sections
-        # /MP enables multithreaded builds (relevant when there are many files).
-        set_target_properties(example PROPERTIES COMPILE_FLAGS "/Os /GL /MP /bigobj")
-        set_target_properties(example PROPERTIES LINK_FLAGS "/LTCG")
+        # /bigobj is needed for bigger binding projects due to the limit to 64k
+        # addressable sections. /MP enables multithreaded builds (relevant when
+        # there are many files).
+        set_target_properties(example PROPERTIES COMPILE_FLAGS "/MP /bigobj ")
+
+        if (NOT ${U_CMAKE_BUILD_TYPE} MATCHES DEBUG)
+          # Enforce size-based optimization and link time code generation on MSVC
+          # (~30% smaller binaries in experiments).
+          set_target_properties(example APPEND_STRING PROPERTY COMPILE_FLAGS "/Os /GL ")
+          set_target_properties(example APPEND_STRING PROPERTY LINK_FLAGS "/LTCG ")
+        endif()
       endif()
 
       # .PYD file extension on Windows