build: Tidy up a bunch of tool Makefiles, and simplify where possible using the
new all-targets pseudo-component.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142401 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/bugpoint-passes/Makefile b/tools/bugpoint-passes/Makefile
index b4ad3e4..61f96bc 100644
--- a/tools/bugpoint-passes/Makefile
+++ b/tools/bugpoint-passes/Makefile
@@ -7,10 +7,10 @@
 #
 ##===----------------------------------------------------------------------===##
 
-LEVEL = ../..
-LIBRARYNAME = BugpointPasses
-LOADABLE_MODULE = 1
-USEDLIBS =
+LEVEL := ../..
+LIBRARYNAME := BugpointPasses
+LOADABLE_MODULE := 1
+USEDLIBS :=
 
 # If we don't need RTTI or EH, there's no reason to export anything
 # from this plugin.