5 files changed, 38 insertions, 3 deletions
diff --git a/Help/command/if.rst b/Help/command/if.rst
index d8e3a45..be992df 100644
--- a/Help/command/if.rst
+++ b/Help/command/if.rst
@@ -29,6 +29,8 @@ If used, it must be a verbatim
 repeat of the argument of the opening
 ``if`` command.
 
+.. _`Condition Syntax`:
+
 Condition Syntax
 ^^^^^^^^^^^^^^^^
 
diff --git a/Modules/CMakeDependentOption.cmake b/Modules/CMakeDependentOption.cmake
index 6046d85..99d5070 100644
--- a/Modules/CMakeDependentOption.cmake
+++ b/Modules/CMakeDependentOption.cmake
@@ -12,7 +12,7 @@ conditions are true.  When the option is not presented a default value
 is used, but any value set by the user is preserved for when the
 option is presented again.  Example invocation:
 
-::
+.. code-block:: cmake
 
   CMAKE_DEPENDENT_OPTION(USE_FOO "Use Foo" ON
                          "USE_BAR;NOT USE_ZOT" OFF)
@@ -21,7 +21,8 @@ If USE_BAR is true and USE_ZOT is false, this provides an option
 called USE_FOO that defaults to ON.  Otherwise, it sets USE_FOO to
 OFF.  If the status of USE_BAR or USE_ZOT ever changes, any value for
 the USE_FOO option is saved so that when the option is re-enabled it
-retains its old value.
+retains its old value.  Each element in the fourth parameter is
+evaluated as an if-condition, so :ref:`Condition Syntax` can be used.
 #]=======================================================================]
 
 macro(CMAKE_DEPENDENT_OPTION option doc default depends force)
diff --git a/Modules/CMakeDetermineCCompiler.cmake b/Modules/CMakeDetermineCCompiler.cmake
index 8be781a..037c33b 100644
--- a/Modules/CMakeDetermineCCompiler.cmake
+++ b/Modules/CMakeDetermineCCompiler.cmake
@@ -124,6 +124,22 @@ if(NOT CMAKE_C_COMPILER_ID_RUN)
   elseif(CMAKE_C_PLATFORM_ID MATCHES "Cygwin")
     set(CMAKE_COMPILER_IS_CYGWIN 1)
   endif()
+else()
+  if(NOT DEFINED CMAKE_C_COMPILER_FRONTEND_VARIANT)
+    # Some toolchain files set our internal CMAKE_C_COMPILER_ID_RUN
+    # variable but are not aware of CMAKE_C_COMPILER_FRONTEND_VARIANT.
+    # They pre-date our support for the GNU-like variant targeting the
+    # MSVC ABI so we do not consider that here.
+    if(CMAKE_C_COMPILER_ID STREQUAL "Clang")
+      if("x${CMAKE_C_SIMULATE_ID}" STREQUAL "xMSVC")
+        set(CMAKE_C_COMPILER_FRONTEND_VARIANT "MSVC")
+      else()
+        set(CMAKE_C_COMPILER_FRONTEND_VARIANT "GNU")
+      endif()
+    else()
+      set(CMAKE_C_COMPILER_FRONTEND_VARIANT "")
+    endif()
+  endif()
 endif()
 
 if (NOT _CMAKE_TOOLCHAIN_LOCATION)
diff --git a/Modules/CMakeDetermineCXXCompiler.cmake b/Modules/CMakeDetermineCXXCompiler.cmake
index 00ef5b9..7274eec 100644
--- a/Modules/CMakeDetermineCXXCompiler.cmake
+++ b/Modules/CMakeDetermineCXXCompiler.cmake
@@ -119,6 +119,22 @@ if(NOT CMAKE_CXX_COMPILER_ID_RUN)
   elseif(CMAKE_CXX_PLATFORM_ID MATCHES "Cygwin")
     set(CMAKE_COMPILER_IS_CYGWIN 1)
   endif()
+else()
+  if(NOT DEFINED CMAKE_CXX_COMPILER_FRONTEND_VARIANT)
+    # Some toolchain files set our internal CMAKE_CXX_COMPILER_ID_RUN
+    # variable but are not aware of CMAKE_CXX_COMPILER_FRONTEND_VARIANT.
+    # They pre-date our support for the GNU-like variant targeting the
+    # MSVC ABI so we do not consider that here.
+    if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+      if("x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
+        set(CMAKE_CXX_COMPILER_FRONTEND_VARIANT "MSVC")
+      else()
+        set(CMAKE_CXX_COMPILER_FRONTEND_VARIANT "GNU")
+      endif()
+    else()
+      set(CMAKE_CXX_COMPILER_FRONTEND_VARIANT "")
+    endif()
+  endif()
 endif()
 
 if (NOT _CMAKE_TOOLCHAIN_LOCATION)
diff --git a/Source/CMakeVersion.cmake b/Source/CMakeVersion.cmake
index 3bbbd28..e6d5e9d 100644
--- a/Source/CMakeVersion.cmake
+++ b/Source/CMakeVersion.cmake
@@ -1,7 +1,7 @@
 # CMake version number components.
 set(CMake_VERSION_MAJOR 3)
 set(CMake_VERSION_MINOR 15)
-set(CMake_VERSION_PATCH 20190805)
+set(CMake_VERSION_PATCH 20190806)
 #set(CMake_VERSION_RC 0)
 set(CMake_VERSION_IS_DIRTY 0)