CMake: Fix missing WIN32 definition on Windows platforms.

Although some Windows compilers still #define WIN32, more and more
standard compliant compilers only #define _WIN32. FLTK *did* #define
WIN32 for all Windows targets with autoconf/configure, but that bit
was lost for CMake builds. This is necessary until we replace WIN32
with _WIN32 throughout the Windows specific code.


git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@12612 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

CMake/setup.cmake

@@ -69,14 +69,19 @@ set(FLTK_DOCDIR ${CMAKE_INSTALL_DATADIR}/doc CACHE PATH
 # platform dependent information
 #######################################################################
 
+# I think this code is useless, so I disabled it by commenting it out.
+# Let's wait and see if it does any harm (user complaints).
+# The real fix is below: add_definitions(-DWIN32).
+# AlbrechtS, Dec 28, 2017.
 # fix no WIN32 defined issue
-if(NOT WIN32)
-    if(_WIN32)
-        set(WIN32 _WIN32)
-    elseif(__WIN32__)
-        set(WIN32 __WIN32__)
-    endif(_WIN32)
-endif(NOT WIN32)
+# if(NOT WIN32)
+#     if(_WIN32)
+#         set(WIN32 _WIN32)
+#     elseif(__WIN32__)
+#         set(WIN32 __WIN32__)
+#     endif(_WIN32)
+# endif(NOT WIN32)
+# End of code commented out on Dec 28, 2017
 
 # set where config files go
 if(WIN32 AND NOT CYGWIN)
@@ -111,6 +116,7 @@ if(APPLE)
 endif(APPLE)
 
 if(WIN32)
+    add_definitions(-DWIN32)
     if(MSVC)
         add_definitions(-DWIN32_LEAN_AND_MEAN)
         add_definitions(-D_CRT_SECURE_NO_WARNINGS)