Cleanup implementation of target builtins code.

- Renamed stdlib-sse.ll to builtins-sse.ll (etc.) in an attempt to better indicate
the fact that the stuff in those files has a role beyond implementing stuff for
the standard library.
- Moved declarations of the various __pseudo_* functions from being done with LLVM
API calls in builtins.cpp to just straight up declarations in LLVM assembly
language in builtins.m4.  (Much less code to do it this way, and more clear what's
going on.)

bitcode2cpp.py

@@ -9,7 +9,7 @@ length=0
 
 src=str(sys.argv[1])
 
-target = re.sub(".*stdlib-", "", src)
+target = re.sub(".*builtins-", "", src)
 target = re.sub("\.ll$", "", target)
 target = re.sub("\.c$", "", target)
 target = re.sub("-", "_", target)
@@ -20,14 +20,14 @@ except IOError:
     print >> sys.stderr, "Couldn't open " + src
     sys.exit(1)
 
-print "unsigned char stdlib_bitcode_" + target + "[] = {"
+print "unsigned char builtins_bitcode_" + target + "[] = {"
 for line in as_out.stdout.readlines():
     length = length + len(line)
     for c in line:
         print ord(c)
         print ", "
 print " 0 };\n\n"
-print "int stdlib_bitcode_" + target + "_length = " + str(length) + ";\n"
+print "int builtins_bitcode_" + target + "_length = " + str(length) + ";\n"
 
 as_out.wait()