[Development] Add possibility to build Windows programs with GNUTLS via cmake.

git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@4241 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9c08e8b..9d5bff7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -85,6 +85,14 @@
     "<CMAKE_RC_COMPILER> <FLAGS> <DEFINES> -o <OBJECT> --output-format=coff <SOURCE>")
 endif()
 
+# Check for GNUTLS library
+find_package(GnuTLS)
+if(GNUTLS_FOUND)
+  include_directories(${GNUTLS_INCLUDE_DIR})
+  add_definitions("-DHAVE_GNUTLS")
+  add_definitions(${GNUTLS_DEFINITIONS})
+endif()
+
 # Generate config.h
 include(CheckIncludeFiles)
 include(CheckFunctionExists)