ENH: Add a depends check step to custom targets. Add support for the IMPLICIT_DEPENDS feature of custom commands when building in custom targets. Convert multiple-output pair checks to be per-target instead of global.

Source/cmMakefileLibraryTargetGenerator.cxx

@@ -47,9 +47,6 @@ void cmMakefileLibraryTargetGenerator::WriteRuleFiles()
   // write the per-target per-language flags
   this->WriteTargetLanguageFlags();
 
-  // Write the dependency generation rule.
-  this->WriteTargetDependRules();
-
   // write the link rules
   // Write the rule for this target type.
   switch(this->Target->GetType())
@@ -85,6 +82,10 @@ void cmMakefileLibraryTargetGenerator::WriteRuleFiles()
   // Write clean target
   this->WriteTargetCleanRules();
 
+  // Write the dependency generation rule.  This must be done last so
+  // that multiple output pair information is available.
+  this->WriteTargetDependRules();
+
   // close the streams
   this->CloseFileStreams();
 }