[LyX/master] Cmake build: remove warnings with newer cmake

[Kornel Benko]

commit f697e50fd38f86202b653c27835ab6d8d50d6f67
Author: Kornel Benko <kor...@lyx.org>
Date:   Fri Aug 23 00:02:56 2013 +0200

    Cmake build: remove warnings with newer cmake
    
    Omit using empty defines in find_path() and find_library()

diff --git a/development/cmake/modules/FindZLIB.cmake 
b/development/cmake/modules/FindZLIB.cmake
index 251e9a2..a46a936 100644
--- a/development/cmake/modules/FindZLIB.cmake
+++ b/development/cmake/modules/FindZLIB.cmake
@@ -9,10 +9,12 @@ if (ZLIB_INCLUDE_DIR)
   set(ZLIB_FIND_QUIETLY TRUE)
 endif()
 
-find_path(ZLIB_INCLUDE_DIR zlib.h PATHS
- /usr/include
- /usr/local/include
- "${GNUWIN32_DIR}"/include)
+set(zlibsearch "/usr/include" "/usr/local/include")
+if (GNUWIN32_DIR)
+  list(APPEND zlibsearch "${GNUWIN32_DIR}/include")
+endif()
+
+find_path(ZLIB_INCLUDE_DIR zlib.h PATHS ${zlibsearch})
 
 find_file(ZLIB_HEADER zlib.h
        PATHS ${ZLIB_INCLUDE_DIR} NO_DEFAULT_PATH)
@@ -25,11 +27,15 @@ find_library(ZLIB_LIBRARY NAMES ${POTENTIAL_Z_LIBS}
        NO_DEFAULT_PATH)
        
 
+set(zlibsearch "C:\\Programme\\Microsoft Visual Studio 8\\VC\\lib")
+if(SYSTEM_LIB_DIRS)
+  list(APPEND zlibsearch ${SYSTEM_LIB_DIRS})
+endif()
+if(GNUWIN32_DIR)
+  list(APPEND zlibsearch "${GNUWIN32_DIR}/lib")
+endif()
 find_library(ZLIB_LIBRARY NAMES ${POTENTIAL_Z_LIBS}
-       PATHS 
-       "C:\\Programme\\Microsoft Visual Studio 8\\VC\\lib"
-       ${SYSTEM_LIB_DIRS}
-       "${GNUWIN32_DIR}"/lib)
+       PATHS ${zlibsearch})
 
 if(ZLIB_INCLUDE_DIR AND ZLIB_LIBRARY)
    set(ZLIB_FOUND TRUE)