diff --git a/CompileFlags.cmake b/CompileFlags.cmake
index a6ff8e046a..5f6a0998fe 100644
--- a/CompileFlags.cmake
+++ b/CompileFlags.cmake
@@ -34,13 +34,13 @@ else()
 endif()
 
 #silence duplicate symbol warnings on AIX
-if(CMAKE_SYSTEM MATCHES "AIX")
+if(CMAKE_SYSTEM_NAME MATCHES "AIX")
   if(NOT CMAKE_COMPILER_IS_GNUCXX)
     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -bhalt:5 ")
   endif()
 endif()
 
-if(CMAKE_SYSTEM MATCHES "IRIX")
+if(CMAKE_SYSTEM_NAME MATCHES "IRIX")
   if(NOT CMAKE_COMPILER_IS_GNUCXX)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wl,-woff84 -no_auto_include")
     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,-woff15")
diff --git a/Modules/CMakeBackwardCompatibilityCXX.cmake b/Modules/CMakeBackwardCompatibilityCXX.cmake
index a3da2d6285..94a94ee53e 100644
--- a/Modules/CMakeBackwardCompatibilityCXX.cmake
+++ b/Modules/CMakeBackwardCompatibilityCXX.cmake
@@ -31,10 +31,10 @@ if(NOT CMAKE_SKIP_COMPATIBILITY_TESTS)
   if(NOT CMAKE_COMPILER_IS_GNUCXX)
     include(TestCXXAcceptsFlag)
     set(CMAKE_TRY_ANSI_CXX_FLAGS "")
-    if(CMAKE_SYSTEM MATCHES "IRIX")
+    if(CMAKE_SYSTEM_NAME MATCHES "IRIX")
       set(CMAKE_TRY_ANSI_CXX_FLAGS "-LANG:std")
     endif()
-    if(CMAKE_SYSTEM MATCHES "OSF")
+    if(CMAKE_SYSTEM_NAME MATCHES "OSF")
       set(CMAKE_TRY_ANSI_CXX_FLAGS "-std strict_ansi -nopure_cname")
     endif()
     # if CMAKE_TRY_ANSI_CXX_FLAGS has something in it, see
diff --git a/Modules/FindThreads.cmake b/Modules/FindThreads.cmake
index b5cc67fe1e..6050dcd236 100644
--- a/Modules/FindThreads.cmake
+++ b/Modules/FindThreads.cmake
@@ -41,7 +41,7 @@ set(CMAKE_REQUIRED_QUIET_SAVE ${CMAKE_REQUIRED_QUIET})
 set(CMAKE_REQUIRED_QUIET ${Threads_FIND_QUIETLY})
 
 # Do we have sproc?
-if(CMAKE_SYSTEM MATCHES IRIX AND NOT CMAKE_THREAD_PREFER_PTHREAD)
+if(CMAKE_SYSTEM_NAME MATCHES IRIX AND NOT CMAKE_THREAD_PREFER_PTHREAD)
   CHECK_INCLUDE_FILES("sys/types.h;sys/prctl.h"  CMAKE_HAVE_SPROC_H)
 endif()
 
@@ -138,13 +138,13 @@ if(CMAKE_THREAD_LIBS_INIT OR CMAKE_HAVE_LIBC_CREATE)
   set(Threads_FOUND TRUE)
 endif()
 
-if(CMAKE_SYSTEM MATCHES "Windows")
+if(CMAKE_SYSTEM_NAME MATCHES "Windows")
   set(CMAKE_USE_WIN32_THREADS_INIT 1)
   set(Threads_FOUND TRUE)
 endif()
 
 if(CMAKE_USE_PTHREADS_INIT)
-  if(CMAKE_SYSTEM MATCHES "HP-UX-*")
+  if(CMAKE_SYSTEM_NAME MATCHES "HP-UX")
     # Use libcma if it exists and can be used.  It provides more
     # symbols than the plain pthread library.  CMA threads
     # have actually been deprecated:
diff --git a/Tests/SubDirSpaces/CMakeLists.txt b/Tests/SubDirSpaces/CMakeLists.txt
index 69f1d6833b..40c265e5f9 100644
--- a/Tests/SubDirSpaces/CMakeLists.txt
+++ b/Tests/SubDirSpaces/CMakeLists.txt
@@ -2,7 +2,7 @@ cmake_minimum_required (VERSION 2.6)
 project(SUBDIR)
 
 # Some systems do not seem to support rpath with spaces.
-if("${CMAKE_SYSTEM}" MATCHES "IRIX|QNX")
+if(CMAKE_SYSTEM_NAME MATCHES "IRIX|QNX")
   set(CMAKE_SKIP_BUILD_RPATH 1)
 endif()