STYLE: use a separate source file for generating CMakeSystem.cmake if CMAKE_TOOLCHAIN_FILE is used

Alex

Modules/CMakeDetermineCCompiler.cmake

@@ -62,6 +62,9 @@ IF(NOT CMAKE_C_COMPILER)
   ENDIF(CMAKE_C_COMPILER_INIT AND NOT CMAKE_C_COMPILER)
 ELSE(NOT CMAKE_C_COMPILER)
 
+  # we only get here if CMAKE_C_COMPILER was specified using -D or a pre-made CMakeCache.txt
+  # (e.g. via ctest) or set in CMAKE_TOOLCHAIN_FILE
+  #
   # if a compiler was specified by the user but without path, 
   # now try to find it with the full path
   # if it is found, force it into the cache, 

Modules/CMakeDetermineSystem.cmake

@@ -26,6 +26,10 @@
 # cygwin                        CYGWIN_NT-5.1
 # MacOSX                        Darwin
 
+
+#set the source file which will be configured to become CMakeSystem.cmake
+SET(_CMAKE_SYSTEM_TEMPLATE_FILE ${CMAKE_ROOT}/Modules/CMakeSystem.cmake.in )
+
 IF(CMAKE_TOOLCHAIN_FILE)
   # at first try to load it as path relative to the directory from which cmake has been run
   INCLUDE("${CMAKE_BINARY_DIR}/${CMAKE_TOOLCHAIN_FILE}" OPTIONAL RESULT_VARIABLE _INCLUDED_TOOLCHAIN_FILE)
@@ -40,6 +44,9 @@ IF(CMAKE_TOOLCHAIN_FILE)
     MESSAGE(FATAL_ERROR "Could not find toolchain file: ${CMAKE_TOOLCHAIN_FILE}") 
   ENDIF(_INCLUDED_TOOLCHAIN_FILE)
 
+  # use a different source file for CMakeSystem.cmake, since it has to hold a bit more information
+  SET(_CMAKE_SYSTEM_TEMPLATE_FILE ${CMAKE_ROOT}/Modules/CMakeSystemWithToolchainFile.cmake.in )
+
   IF(NOT DEFINED CMAKE_CROSSCOMPILING)
     SET(CMAKE_CROSSCOMPILING TRUE)
   ENDIF(NOT DEFINED CMAKE_CROSSCOMPILING)
@@ -105,8 +112,8 @@ ENDIF(CMAKE_SYSTEM_VERSION)
 FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log 
   "The system is: ${CMAKE_SYSTEM_NAME} - ${CMAKE_SYSTEM_VERSION} - ${CMAKE_SYSTEM_PROCESSOR}\n")
 
-# configure variables set in this file for fast reload
-CONFIGURE_FILE(${CMAKE_ROOT}/Modules/CMakeSystem.cmake.in 
+# configure variables set in this file for fast reload, the template file is defined at the top of this file
+CONFIGURE_FILE(${_CMAKE_SYSTEM_TEMPLATE_FILE}
                ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeSystem.cmake 
                IMMEDIATE @ONLY)
 

Modules/CMakeLists.txt

@@ -1,5 +1,5 @@
 # just install the modules
-# new file added, force rerunning cmake
+# new file added, force rerunning cmake #
 
 SUBDIRS(Platform)
 INSTALL_FILES(${CMAKE_DATA_DIR}/Modules .*\\.cmake$)

Modules/CMakeSystem.cmake.in

@@ -1,21 +1,6 @@
-IF("@CMAKE_TOOLCHAIN_FILE@" STREQUAL "")
-
-  SET(CMAKE_SYSTEM "@CMAKE_SYSTEM@")
-  SET(CMAKE_SYSTEM_NAME "@CMAKE_SYSTEM_NAME@")
-  SET(CMAKE_SYSTEM_VERSION "@CMAKE_SYSTEM_VERSION@")
-  SET(CMAKE_SYSTEM_PROCESSOR "@CMAKE_SYSTEM_PROCESSOR@")
-  
-ELSE("@CMAKE_TOOLCHAIN_FILE@" STREQUAL "")
-
-  INCLUDE("@CMAKE_TOOLCHAIN_FILE@")
-
-# set CMAKE_SYSTEM to the CMAKE_SYSTEM_NAME
-  SET(CMAKE_SYSTEM  ${CMAKE_SYSTEM_NAME})
-# if there is a CMAKE_SYSTEM_VERSION then add a -${CMAKE_SYSTEM_VERSION}
-  IF(CMAKE_SYSTEM_VERSION)
-    SET(CMAKE_SYSTEM ${CMAKE_SYSTEM}-${CMAKE_SYSTEM_VERSION})
-  ENDIF(CMAKE_SYSTEM_VERSION)
-
-ENDIF("@CMAKE_TOOLCHAIN_FILE@" STREQUAL "")
+SET(CMAKE_SYSTEM "@CMAKE_SYSTEM@")
+SET(CMAKE_SYSTEM_NAME "@CMAKE_SYSTEM_NAME@")
+SET(CMAKE_SYSTEM_VERSION "@CMAKE_SYSTEM_VERSION@")
+SET(CMAKE_SYSTEM_PROCESSOR "@CMAKE_SYSTEM_PROCESSOR@")
 
 SET(CMAKE_SYSTEM_LOADED 1)

Modules/CMakeSystemWithToolchainFile.cmake.in

@@ -0,0 +1,11 @@
+
+INCLUDE("@CMAKE_TOOLCHAIN_FILE@")
+
+# set CMAKE_SYSTEM to the CMAKE_SYSTEM_NAME
+SET(CMAKE_SYSTEM  ${CMAKE_SYSTEM_NAME})
+# if there is a CMAKE_SYSTEM_VERSION then add a -${CMAKE_SYSTEM_VERSION}
+IF(CMAKE_SYSTEM_VERSION)
+  SET(CMAKE_SYSTEM ${CMAKE_SYSTEM}-${CMAKE_SYSTEM_VERSION})
+ENDIF(CMAKE_SYSTEM_VERSION)
+
+SET(CMAKE_SYSTEM_LOADED 1)