Define CMS_DLL in the header as that is how we build it

Otherwise code using the lcms2 we build won't get the stdcall
decorations and linking will fail.

lcms2/lcms2-windows-export.patch

+--- misc/build/lcms2-2.3/include/lcms2.h.sav	2011-12-15 16:45:47.000000000 +0100
++++ misc/build/lcms2-2.3/include/lcms2.h	2012-03-17 22:53:28.731585981 +0100
+@@ -192,6 +192,15 @@ typedef int                  cmsBool;
+ # endif
+ #endif
+ 
++// LibreOffice always builds this as DLL and with the stdcall calling
++// convention, so make this usable from outside without having to
++// specify CMS_DLL manually whenever the library is used.
++#ifndef CMS_DLL_BUILD
++#ifndef CMS_DLL
++#define CMS_DLL
++#endif
++#endif
++
+ // Calling convention -- this is hardly platform and compiler dependent
+ #ifdef CMS_IS_WINDOWS_
+ #  if defined(CMS_DLL) || defined(CMS_DLL_BUILD)

lcms2/makefile.mk

@@ -39,7 +39,7 @@ TARGET=so_lcms2
 TARFILE_NAME=lcms2-2.3
 TARFILE_MD5=327348d67c979c88c2dec59a23a17d85
 
-PATCH_FILES = lcms2.patch
+PATCH_FILES = lcms2.patch lcms2-windows-export.patch
 
 .IF "$(SYSTEM_LCMS2)" == "YES"
 @all: