7 files changed, 35 insertions, 21 deletions
diff --git a/Modules/Compiler/AppleClang-C.cmake b/Modules/Compiler/AppleClang-C.cmake
index 1db7d9e..5908c26 100644
--- a/Modules/Compiler/AppleClang-C.cmake
+++ b/Modules/Compiler/AppleClang-C.cmake
@@ -13,10 +13,12 @@ if(NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.0)
 endif()
 
 if(NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.0)
-  if (NOT CMAKE_C_STANDARD_COMPUTED_DEFAULT)
-    message(FATAL_ERROR "CMAKE_C_STANDARD_COMPUTED_DEFAULT should be set for ${CMAKE_C_COMPILER_ID} (${CMAKE_C_COMPILER}) version ${CMAKE_C_COMPILER_VERSION}")
+  if (NOT CMAKE_C_COMPILER_FORCED)
+    if (NOT CMAKE_C_STANDARD_COMPUTED_DEFAULT)
+      message(FATAL_ERROR "CMAKE_C_STANDARD_COMPUTED_DEFAULT should be set for ${CMAKE_C_COMPILER_ID} (${CMAKE_C_COMPILER}) version ${CMAKE_C_COMPILER_VERSION}")
+    endif()
+    set(CMAKE_C_STANDARD_DEFAULT ${CMAKE_C_STANDARD_COMPUTED_DEFAULT})
   endif()
-  set(CMAKE_C_STANDARD_DEFAULT ${CMAKE_C_STANDARD_COMPUTED_DEFAULT})
 endif()
 
 macro(cmake_record_c_compile_features)
diff --git a/Modules/Compiler/AppleClang-CXX.cmake b/Modules/Compiler/AppleClang-CXX.cmake
index 031851a..c4e342b 100644
--- a/Modules/Compiler/AppleClang-CXX.cmake
+++ b/Modules/Compiler/AppleClang-CXX.cmake
@@ -23,10 +23,12 @@ elseif(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.1)
 endif()
 
 if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.0)
-  if (NOT CMAKE_CXX_STANDARD_COMPUTED_DEFAULT)
-    message(FATAL_ERROR "CMAKE_CXX_STANDARD_COMPUTED_DEFAULT should be set for ${CMAKE_CXX_COMPILER_ID} (${CMAKE_CXX_COMPILER}) version ${CMAKE_CXX_COMPILER_VERSION}")
+  if (NOT CMAKE_CXX_COMPILER_FORCED)
+    if (NOT CMAKE_CXX_STANDARD_COMPUTED_DEFAULT)
+      message(FATAL_ERROR "CMAKE_CXX_STANDARD_COMPUTED_DEFAULT should be set for ${CMAKE_CXX_COMPILER_ID} (${CMAKE_CXX_COMPILER}) version ${CMAKE_CXX_COMPILER_VERSION}")
+    endif()
+    set(CMAKE_CXX_STANDARD_DEFAULT ${CMAKE_CXX_STANDARD_COMPUTED_DEFAULT})
   endif()
-  set(CMAKE_CXX_STANDARD_DEFAULT ${CMAKE_CXX_STANDARD_COMPUTED_DEFAULT})
 endif()
 
 
diff --git a/Modules/Compiler/Clang-C.cmake b/Modules/Compiler/Clang-C.cmake
index ef3a46a..a2e81c1 100644
--- a/Modules/Compiler/Clang-C.cmake
+++ b/Modules/Compiler/Clang-C.cmake
@@ -18,10 +18,12 @@ if(NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 3.4)
 endif()
 
 if(NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 3.4)
-  if (NOT CMAKE_C_STANDARD_COMPUTED_DEFAULT)
-    message(FATAL_ERROR "CMAKE_C_STANDARD_COMPUTED_DEFAULT should be set for ${CMAKE_C_COMPILER_ID} (${CMAKE_C_COMPILER}) version ${CMAKE_C_COMPILER_VERSION}")
+  if (NOT CMAKE_C_COMPILER_FORCED)
+    if (NOT CMAKE_C_STANDARD_COMPUTED_DEFAULT)
+      message(FATAL_ERROR "CMAKE_C_STANDARD_COMPUTED_DEFAULT should be set for ${CMAKE_C_COMPILER_ID} (${CMAKE_C_COMPILER}) version ${CMAKE_C_COMPILER_VERSION}")
+    endif()
+    set(CMAKE_C_STANDARD_DEFAULT ${CMAKE_C_STANDARD_COMPUTED_DEFAULT})
   endif()
-  set(CMAKE_C_STANDARD_DEFAULT ${CMAKE_C_STANDARD_COMPUTED_DEFAULT})
 endif()
 
 macro(cmake_record_c_compile_features)
diff --git a/Modules/Compiler/Clang-CXX.cmake b/Modules/Compiler/Clang-CXX.cmake
index fcc7319..055a8ee 100644
--- a/Modules/Compiler/Clang-CXX.cmake
+++ b/Modules/Compiler/Clang-CXX.cmake
@@ -32,10 +32,12 @@ elseif(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 3.4)
 endif()
 
 if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 3.4)
-  if (NOT CMAKE_CXX_STANDARD_COMPUTED_DEFAULT)
-    message(FATAL_ERROR "CMAKE_CXX_STANDARD_COMPUTED_DEFAULT should be set for ${CMAKE_CXX_COMPILER_ID} (${CMAKE_CXX_COMPILER}) version ${CMAKE_CXX_COMPILER_VERSION}")
+  if (NOT CMAKE_CXX_COMPILER_FORCED)
+    if (NOT CMAKE_CXX_STANDARD_COMPUTED_DEFAULT)
+      message(FATAL_ERROR "CMAKE_CXX_STANDARD_COMPUTED_DEFAULT should be set for ${CMAKE_CXX_COMPILER_ID} (${CMAKE_CXX_COMPILER}) version ${CMAKE_CXX_COMPILER_VERSION}")
+    endif()
+    set(CMAKE_CXX_STANDARD_DEFAULT ${CMAKE_CXX_STANDARD_COMPUTED_DEFAULT})
   endif()
-  set(CMAKE_CXX_STANDARD_DEFAULT ${CMAKE_CXX_STANDARD_COMPUTED_DEFAULT})
 endif()
 
 macro(cmake_record_cxx_compile_features)
diff --git a/Modules/Compiler/GNU-C.cmake b/Modules/Compiler/GNU-C.cmake
index 5c68b1e..d979fb7 100644
--- a/Modules/Compiler/GNU-C.cmake
+++ b/Modules/Compiler/GNU-C.cmake
@@ -23,10 +23,12 @@ elseif (NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.6)
 endif()
 
 if(NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.4)
-  if (NOT CMAKE_C_STANDARD_COMPUTED_DEFAULT)
-    message(FATAL_ERROR "CMAKE_C_STANDARD_COMPUTED_DEFAULT should be set for ${CMAKE_C_COMPILER_ID} (${CMAKE_C_COMPILER}) version ${CMAKE_C_COMPILER_VERSION}")
+  if (NOT CMAKE_C_COMPILER_FORCED)
+    if (NOT CMAKE_C_STANDARD_COMPUTED_DEFAULT)
+      message(FATAL_ERROR "CMAKE_C_STANDARD_COMPUTED_DEFAULT should be set for ${CMAKE_C_COMPILER_ID} (${CMAKE_C_COMPILER}) version ${CMAKE_C_COMPILER_VERSION}")
+    endif()
+    set(CMAKE_C_STANDARD_DEFAULT ${CMAKE_C_STANDARD_COMPUTED_DEFAULT})
   endif()
-  set(CMAKE_C_STANDARD_DEFAULT ${CMAKE_C_STANDARD_COMPUTED_DEFAULT})
 endif()
 
 
diff --git a/Modules/Compiler/GNU-CXX.cmake b/Modules/Compiler/GNU-CXX.cmake
index cbb0293..a7e71c3 100644
--- a/Modules/Compiler/GNU-CXX.cmake
+++ b/Modules/Compiler/GNU-CXX.cmake
@@ -35,10 +35,12 @@ elseif (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.8)
 endif()
 
 if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.4)
-  if (NOT CMAKE_CXX_STANDARD_COMPUTED_DEFAULT)
-    message(FATAL_ERROR "CMAKE_CXX_STANDARD_COMPUTED_DEFAULT should be set for ${CMAKE_CXX_COMPILER_ID} (${CMAKE_CXX_COMPILER}) version ${CMAKE_CXX_COMPILER_VERSION}")
+  if (NOT CMAKE_CXX_COMPILER_FORCED)
+    if (NOT CMAKE_CXX_STANDARD_COMPUTED_DEFAULT)
+      message(FATAL_ERROR "CMAKE_CXX_STANDARD_COMPUTED_DEFAULT should be set for ${CMAKE_CXX_COMPILER_ID} (${CMAKE_CXX_COMPILER}) version ${CMAKE_CXX_COMPILER_VERSION}")
+    endif()
+    set(CMAKE_CXX_STANDARD_DEFAULT ${CMAKE_CXX_STANDARD_COMPUTED_DEFAULT})
   endif()
-  set(CMAKE_CXX_STANDARD_DEFAULT ${CMAKE_CXX_STANDARD_COMPUTED_DEFAULT})
 endif()
 
 macro(cmake_record_cxx_compile_features)
diff --git a/Modules/Compiler/SunPro-CXX.cmake b/Modules/Compiler/SunPro-CXX.cmake
index ff68ee9..50d68ee 100644
--- a/Modules/Compiler/SunPro-CXX.cmake
+++ b/Modules/Compiler/SunPro-CXX.cmake
@@ -37,10 +37,12 @@ if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.13)
 endif()
 
 if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.13)
-  if (NOT CMAKE_CXX_STANDARD_COMPUTED_DEFAULT)
-    message(FATAL_ERROR "CMAKE_CXX_STANDARD_COMPUTED_DEFAULT should be set for ${CMAKE_CXX_COMPILER_ID} (${CMAKE_CXX_COMPILER}) version ${CMAKE_CXX_COMPILER_VERSION}")
+  if (NOT CMAKE_CXX_COMPILER_FORCED)
+    if (NOT CMAKE_CXX_STANDARD_COMPUTED_DEFAULT)
+      message(FATAL_ERROR "CMAKE_CXX_STANDARD_COMPUTED_DEFAULT should be set for ${CMAKE_CXX_COMPILER_ID} (${CMAKE_CXX_COMPILER}) version ${CMAKE_CXX_COMPILER_VERSION}")
+    endif()
+    set(CMAKE_CXX_STANDARD_DEFAULT ${CMAKE_CXX_STANDARD_COMPUTED_DEFAULT})
   endif()
-  set(CMAKE_CXX_STANDARD_DEFAULT ${CMAKE_CXX_STANDARD_COMPUTED_DEFAULT})
 endif()
 
 macro(cmake_record_cxx_compile_features)