Re-enable support for --program-prefix.

The Apple buildbots have been modified not to pass --target,
so they shouldn't choke on a default program prefix anymore.

Patch by Rick Foos!

llvm-svn: 164956
diff --git a/llvm/projects/sample/Makefile.llvm.rules b/llvm/projects/sample/Makefile.llvm.rules
index a655302..7ed1c1b 100644
--- a/llvm/projects/sample/Makefile.llvm.rules
+++ b/llvm/projects/sample/Makefile.llvm.rules
@@ -1437,7 +1437,7 @@
 uninstall-local::
 	$(Echo) Uninstall circumvented with NO_INSTALL
 else
-DestTool = $(DESTDIR)$(PROJ_bindir)/$(TOOLEXENAME)
+DestTool = $(DESTDIR)$(PROJ_bindir)/$(program_prefix)$(TOOLEXENAME)
 
 install-local:: $(DestTool)
 
@@ -1451,7 +1451,7 @@
 
 # TOOLALIAS install.
 ifdef TOOLALIAS
-DestToolAlias = $(DESTDIR)$(PROJ_bindir)/$(TOOLALIAS)$(EXEEXT)
+DestToolAlias = $(DESTDIR)$(PROJ_bindir)/$(program_prefix)$(TOOLALIAS)$(EXEEXT)
 
 install-local:: $(DestToolAlias)