Use --sysroot when cross compiling.

As CMAKE_ROOT_FIND_PATH can be a list, a new CMAKE_SYSROOT is
introduced, which is never a list.

The contents of this variable is passed to supporting compilers
as --sysroot. It is also accounted for when processing implicit
link directories reported by the compiler, and when generating
RPATH information.

1 files changed, 20 insertions, 4 deletions

diff --git a/Source/cmFindCommon.cxx b/Source/cmFindCommon.cxx
index b44864e..5daa47d 100644
--- a/Source/cmFindCommon.cxx
+++ b/Source/cmFindCommon.cxx
@@ -62,10 +62,15 @@ void cmFindCommon::GenerateDocumentation()
     "The CMake variable CMAKE_FIND_ROOT_PATH specifies one or more "
     "directories to be prepended to all other search directories. "
     "This effectively \"re-roots\" the entire search under given locations. "
-    "By default it is empty. It is especially useful when "
+    "By default it is empty.  "
+    "The variable CMAKE_SYSROOT can also be used to specify exactly one "
+    "directory to use as a prefix.  Setting CMAKE_SYSROOT also has other "
+    "effects.  See the documentation for that variable for more.  "
+    "These are especially useful when "
     "cross-compiling to point to the root directory of the "
     "target environment and CMake will search there too. By default at first "
-    "the directories listed in CMAKE_FIND_ROOT_PATH and then the non-rooted "
+    "the CMAKE_SYSROOT directory is searched, then the directories listed in "
+    "CMAKE_FIND_ROOT_PATH and then the non-rooted "
     "directories will be searched. "
     "The default behavior can be adjusted by setting "
     "CMAKE_FIND_ROOT_PATH_MODE_XXX.  This behavior can be manually "
@@ -187,16 +192,27 @@ void cmFindCommon::RerootPaths(std::vector<std::string>& paths)
     {
     return;
     }
+  const char* sysroot =
+    this->Makefile->GetDefinition("CMAKE_SYSROOT");
   const char* rootPath =
     this->Makefile->GetDefinition("CMAKE_FIND_ROOT_PATH");
-  if((rootPath == 0) || (strlen(rootPath) == 0))
+  const bool noSysroot = !sysroot || !*sysroot;
+  const bool noRootPath = !rootPath || !*rootPath;
+  if(noSysroot && noRootPath)
     {
     return;
     }
 
   // Construct the list of path roots with no trailing slashes.
   std::vector<std::string> roots;
-  cmSystemTools::ExpandListArgument(rootPath, roots);
+  if (sysroot)
+    {
+    roots.push_back(sysroot);
+    }
+  if (rootPath)
+    {
+    cmSystemTools::ExpandListArgument(rootPath, roots);
+    }
   for(std::vector<std::string>::iterator ri = roots.begin();
       ri != roots.end(); ++ri)
     {