ENH: Patch from Alexander Neundorf to improve behavior.

Modules/CheckCSourceCompiles.cmake

@@ -15,10 +15,14 @@ MACRO(CHECK_C_SOURCE_COMPILES SOURCE VAR)
     IF(CMAKE_REQUIRED_LIBRARIES)
       SET(CHECK_C_SOURCE_COMPILES_ADD_LIBRARIES
         "-DLINK_LIBRARIES:STRING=${CMAKE_REQUIRED_LIBRARIES}")
+    ELSE(CMAKE_REQUIRED_LIBRARIES)
+      SET(CHECK_C_SOURCE_COMPILES_ADD_LIBRARIES)
     ENDIF(CMAKE_REQUIRED_LIBRARIES)
     IF(CMAKE_REQUIRED_INCLUDES)
       SET(CHECK_C_SOURCE_COMPILES_ADD_INCLUDES
         "-DINCLUDE_DIRECTORIES:STRING=${CMAKE_REQUIRED_INCLUDES}")
+    ELSE(CMAKE_REQUIRED_INCLUDES)
+      SET(CHECK_C_SOURCE_COMPILES_ADD_INCLUDES)
     ENDIF(CMAKE_REQUIRED_INCLUDES)
     FILE(WRITE "${CMAKE_BINARY_DIR}/CMakeFiles/CMakeTmp/src.c"
       "${SOURCE}")

Modules/CheckCXXSourceCompiles.cmake

@@ -15,10 +15,14 @@ MACRO(CHECK_CXX_SOURCE_COMPILES SOURCE VAR)
     IF(CMAKE_REQUIRED_LIBRARIES)
       SET(CHECK_CXX_SOURCE_COMPILES_ADD_LIBRARIES
         "-DLINK_LIBRARIES:STRING=${CMAKE_REQUIRED_LIBRARIES}")
+    ELSE(CMAKE_REQUIRED_LIBRARIES)
+      SET(CHECK_CXX_SOURCE_COMPILES_ADD_LIBRARIES)
     ENDIF(CMAKE_REQUIRED_LIBRARIES)
     IF(CMAKE_REQUIRED_INCLUDES)
       SET(CHECK_CXX_SOURCE_COMPILES_ADD_INCLUDES
         "-DINCLUDE_DIRECTORIES:STRING=${CMAKE_REQUIRED_INCLUDES}")
+    ELSE(CMAKE_REQUIRED_INCLUDES)
+      SET(CHECK_CXX_SOURCE_COMPILES_ADD_INCLUDES)
     ENDIF(CMAKE_REQUIRED_INCLUDES)
     FILE(WRITE "${CMAKE_BINARY_DIR}/CMakeFiles/CMakeTmp/src.cxx"
       "${SOURCE}")

Modules/CheckIncludeFiles.cmake

@@ -7,10 +7,16 @@
 #   
 # If CMAKE_REQUIRED_FLAGS is set then those flags will be passed into the
 # compile of the program
-
+# If CMAKE_REQUIRED_INCLUDES is set then those directories will be passed
+# as include paths to the compiler
 
 MACRO(CHECK_INCLUDE_FILES INCLUDE VARIABLE)
   IF("${VARIABLE}" MATCHES "^${VARIABLE}$")
+    IF(CMAKE_REQUIRED_INCLUDES)
+      SET(CHECK_INCLUDE_FILES_INCLUDE_DIRS "-DINCLUDE_DIRECTORIES=${CMAKE_REQUIRED_INCLUDES}")
+    ELSE(CMAKE_REQUIRED_INCLUDES)
+      SET(CHECK_INCLUDE_FILES_INCLUDE_DIRS)
+    ENDIF(CMAKE_REQUIRED_INCLUDES)
     SET(CHECK_INCLUDE_FILES_CONTENT "/* */\n")
     SET(MACRO_CHECK_INCLUDE_FILES_FLAGS ${CMAKE_REQUIRED_FLAGS})
     FOREACH(FILE ${INCLUDE})
@@ -28,6 +34,7 @@ MACRO(CHECK_INCLUDE_FILES INCLUDE VARIABLE)
       ${CMAKE_BINARY_DIR}/CMakeFiles/CMakeTmp/CheckIncludeFiles.c
       CMAKE_FLAGS 
       -DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_INCLUDE_FILES_FLAGS}
+      "${CHECK_INCLUDE_FILES_INCLUDE_DIRS}"
       OUTPUT_VARIABLE OUTPUT)
     IF(${VARIABLE})
       MESSAGE(STATUS "Looking for include files ${VARIABLE} - found")