- Modified CMakeLists to support zlib

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 689d563..bae87e3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -17,6 +17,8 @@
 
 option(USE_PKCS11_HELPER_LIBRARY "Build PolarSSL with the pkcs11-helper library." OFF)
 
+option(ENABLE_ZLIB_SUPPORT "Build PolarSSL with zlib library." OFF)
+
 if(LIB_INSTALL_DIR)
 else()
 set(LIB_INSTALL_DIR lib)
@@ -24,6 +26,14 @@
 
 include_directories(include/)
 
+if(ENABLE_ZLIB_SUPPORT)
+  find_package(ZLIB)
+
+  if(ZLIB_FOUND)
+    include_directories(ZLIB_INCLUDE_DIR)
+  endif(ZLIB_FOUND)
+endif(ENABLE_ZLIB_SUPPORT)
+
 add_subdirectory(library)
 add_subdirectory(include)