Switch to using a fake llvm-config program, so there's just one setup.py

This should help keep windows and other platforms in synch
easier.

llvm-config-win32.py

@@ -0,0 +1,70 @@
+import sys, os
+
+def find_path_of(filename):
+    """Finds the path from $PATH where the file exists, returns None if not found."""
+    pathlist = os.getenv('PATH').split(os.pathsep)
+    for path in pathlist:
+        if os.path.exists(os.path.join(path, filename)):
+            return os.path.abspath(path)
+    return None
+
+if sys.argv[1] == '--version':
+    cmd = 'llvm-tblgen --version'
+    # Hardcoded extraction, only tested on llvm 3.1
+    result = os.popen(cmd).read().split('\n')[1].strip().split(' ')[2]
+    print result
+elif sys.argv[1] == '--libs':
+    # NOTE: instead of actually looking at the components requested,
+    #       we just spit out a bunch of libs
+    for lib in """
+LLVMAnalysis
+LLVMAsmParser
+LLVMAsmPrinter
+LLVMBitReader
+LLVMBitWriter
+LLVMCodeGen
+LLVMCore
+LLVMExecutionEngine
+LLVMInstCombine
+LLVMInstrumentation
+LLVMInterpreter
+LLVMipa
+LLVMipo
+LLVMJIT
+LLVMLinker
+LLVMMC
+LLVMMCParser
+LLVMScalarOpts
+LLVMSelectionDAG
+LLVMSupport
+LLVMTarget
+LLVMTransformUtils
+LLVMVectorize
+LLVMX86AsmParser
+LLVMX86AsmPrinter
+LLVMX86CodeGen
+LLVMX86Desc
+LLVMX86Info
+LLVMX86Utils
+Advapi32
+Shell32
+""".split():
+        print('-l%s' % lib)
+elif sys.argv[1] == '--includedir': 
+    llvmbin = find_path_of('llvm-tblgen.exe')
+    if llvmbin is None:
+        raise RuntimeError('Could not find LLVM')
+    incdir = os.path.abspath(os.path.join(llvmbin, '../include'))
+    if not os.path.exists(os.path.join(incdir, 'llvm/BasicBlock.h')):
+        raise RuntimeError('Could not find LLVM include dir')
+    print incdir
+elif sys.argv[1] == '--libdir': 
+    llvmbin = find_path_of('llvm-tblgen.exe')
+    if llvmbin is None:
+        raise RuntimeError('Could not find LLVM')
+    libdir = os.path.abspath(os.path.join(llvmbin, '../lib'))
+    if not os.path.exists(os.path.join(libdir, 'LLVMCore.lib')):
+        raise RuntimeError('Could not find LLVM lib dir')
+    print libdir
+else:
+    raise RuntimeError('Unrecognized llvm-config command %s' % sys.argv[1])