Simplify some calls to cmGlobalGenerator::Build

Code paths that look up CMAKE_MAKE_PROGRAM from the cache only to
pass it to Build, which only passes it to GenerateBuildCommand,
no longer need to do so.  GenerateBuildCommand now knows how to
look up CMAKE_MAKE_PROGRAM in the cache when no explicit value
is given, so simply pass 0 now.

Source/cmGlobalGenerator.cxx

@@ -1562,15 +1562,6 @@ int cmGlobalGenerator::TryCompile(const char *srcdir, const char *bindir,
                                         this->FirstTimeProgress);
     }
 
-  std::string makeCommand = this->CMakeInstance->
-    GetCacheManager()->GetCacheValue("CMAKE_MAKE_PROGRAM");
-  if(makeCommand.size() == 0)
-    {
-    cmSystemTools::Error(
-      "Generator cannot find the appropriate make command.");
-    return 1;
-    }
-
   std::string newTarget;
   if (target && strlen(target))
     {
@@ -1590,7 +1581,7 @@ int cmGlobalGenerator::TryCompile(const char *srcdir, const char *bindir,
   const char* config = mf->GetDefinition("CMAKE_TRY_COMPILE_CONFIGURATION");
   return this->Build(srcdir,bindir,projectName,
                      newTarget.c_str(),
-                     output,makeCommand.c_str(),config,false,fast,
+                     output,0,config,false,fast,
                      this->TryCompileTimeout);
 }
 

Source/cmake.cxx

@@ -2663,23 +2663,16 @@ int cmake::Build(const std::string& dir,
     this->CreateGlobalGenerator(it.GetValue()));
   std::string output;
   std::string projName;
-  std::string makeProgram;
   if(!it.Find("CMAKE_PROJECT_NAME"))
     {
     std::cerr << "Error: could not find CMAKE_PROJECT_NAME in Cache\n";
     return 1;
     }
   projName = it.GetValue();
-  if(!it.Find("CMAKE_MAKE_PROGRAM"))
-    {
-    std::cerr << "Error: could not find CMAKE_MAKE_PROGRAM in Cache\n";
-    return 1;
-    }
-  makeProgram = it.GetValue();
   return gen->Build(0, dir.c_str(),
                     projName.c_str(), target.c_str(),
                     &output,
-                    makeProgram.c_str(),
+                    0,
                     config.c_str(), clean, false, 0,
                     cmSystemTools::OUTPUT_PASSTHROUGH,
                     nativeOptions);