diff --git a/Modules/CMakeBackwardCompatibilityC.cmake b/Modules/CMakeBackwardCompatibilityC.cmake
index c9dbce1c9..90dfbfc85 100644
--- a/Modules/CMakeBackwardCompatibilityC.cmake
+++ b/Modules/CMakeBackwardCompatibilityC.cmake
@@ -21,9 +21,11 @@ IF(NOT CMAKE_SKIP_COMPATIBILITY_TESTS)
   INCLUDE (CheckIncludeFile)
   CHECK_INCLUDE_FILE("limits.h"       CMAKE_HAVE_LIMITS_H)
   CHECK_INCLUDE_FILE("unistd.h"       CMAKE_HAVE_UNISTD_H)
-  CHECK_INCLUDE_FILE("sys/prctl.h"    CMAKE_HAVE_SYS_PRCTL_H)
   CHECK_INCLUDE_FILE("pthread.h"      CMAKE_HAVE_PTHREAD_H)
 
+  INCLUDE (CheckIncludeFiles)
+  CHECK_INCLUDE_FILES("sys/types.h;sys/prctl.h"    CMAKE_HAVE_SYS_PRCTL_H)
+
   INCLUDE (TestBigEndian)
   TEST_BIG_ENDIAN(CMAKE_WORDS_BIGENDIAN)
   INCLUDE (FindX11)
diff --git a/Modules/FindThreads.cmake b/Modules/FindThreads.cmake
index e0bc48088..af2801bf9 100644
--- a/Modules/FindThreads.cmake
+++ b/Modules/FindThreads.cmake
@@ -7,11 +7,12 @@
 # CMAKE_HP_PTHREADS_INIT             - are we using hp pthreads
 
 INCLUDE (CheckIncludeFile)
+INCLUDE (CheckIncludeFiles)
 INCLUDE (CheckLibraryExists)
 
 # Do we have sproc?
 IF(CMAKE_SYSTEM MATCHES IRIX)
-  CHECK_INCLUDE_FILE("sys/prctl.h"  CMAKE_HAVE_SPROC_H)
+  CHECK_INCLUDE_FILES("sys/types.h;sys/prctl.h"  CMAKE_HAVE_SPROC_H)
 ENDIF(CMAKE_SYSTEM MATCHES IRIX)
 
 IF(CMAKE_HAVE_SPROC_H)