Create a proper target machine for PNaCl.

lib/Target/PNaCl/MCTargetDesc/LLVMBuild.txt

Index: lib/Target/PNaCl/MCTargetDesc/LLVMBuild.txt
diff --git a/lib/IR/LLVMBuild.txt b/lib/Target/PNaCl/MCTargetDesc/LLVMBuild.txt
similarity index 79%
copy from lib/IR/LLVMBuild.txt
copy to lib/Target/PNaCl/MCTargetDesc/LLVMBuild.txt
index cd90ef5b16b65262c123675dd5c126a0a191f890..7d1c684149d02aaf08e60d7eb3498a47d7f0fc82 100644
--- a/lib/IR/LLVMBuild.txt
+++ b/lib/Target/PNaCl/MCTargetDesc/LLVMBuild.txt
@@ -1,4 +1,4 @@
-;===- ./lib/IR/LLVMBuild.txt -----------------------------------*- Conf -*--===;
+;===- ./lib/Target/PNaCl/MCTargetDesc/LLVMBuild.txt --------------*- Conf -*--===;
 ;
 ;                     The LLVM Compiler Infrastructure
 ;
@@ -17,6 +17,6 @@
 
 [component_0]
 type = Library
-name = Core
-parent = Libraries
-required_libraries = Support
+name = PNaClDesc
+parent = PNaCl
+add_to_library_groups = PNaCl