ENH: Added support for building kwsys with GCC visibility support.

When kwsys is built using GCC visibility support can be used. This is similar
to the way that Windows exports symbols in DLLs, and requires projects that
build kwsys to change the default visibility using some compiler flags. See
http://gcc.gnu.org/wiki/Visibility for more details about GCC visibility.

Configure.h.in

@@ -88,11 +88,15 @@
 #endif
 
 /* Setup the export macro.  */
-#if defined(_WIN32) && @KWSYS_BUILD_SHARED@
-# if defined(@KWSYS_NAMESPACE@_EXPORTS)
-#  define @KWSYS_NAMESPACE@_EXPORT __declspec(dllexport)
-# else
-#  define @KWSYS_NAMESPACE@_EXPORT __declspec(dllimport)
+#if @KWSYS_BUILD_SHARED@
+# if defined(_WIN32) || defined(__CYGWIN__)
+#  if defined(@KWSYS_NAMESPACE@_EXPORTS)
+#   define @KWSYS_NAMESPACE@_EXPORT __declspec(dllexport)
+#  else
+#   define @KWSYS_NAMESPACE@_EXPORT __declspec(dllimport)
+#  endif
+# elif __GNUC__ >= 4
+#  define @KWSYS_NAMESPACE@_EXPORT __attribute__ ((visibility("default")))
 # endif
 #else
 # define @KWSYS_NAMESPACE@_EXPORT

kwsysDateStamp.cmake

@@ -12,10 +12,10 @@
 #=============================================================================
 
 # KWSys version date year component.  Format is CCYY.
-SET(KWSYS_DATE_STAMP_YEAR  2009)
+SET(KWSYS_DATE_STAMP_YEAR  2010)
 
 # KWSys version date month component.  Format is MM.
-SET(KWSYS_DATE_STAMP_MONTH 12)
+SET(KWSYS_DATE_STAMP_MONTH 01)
 
 # KWSys version date day component.  Format is DD.
-SET(KWSYS_DATE_STAMP_DAY   16)
+SET(KWSYS_DATE_STAMP_DAY   06)