Various fixes for x86_64 on linux

Configure LLVM correctly, use the right data layout, add the readlink
function back, fix C constants, etc.

configure

@@ -339,7 +339,7 @@ if [ -z "$CFG_TARGET_TRIPLES" ]
 then
     CFG_TARGET_TRIPLES="${CFG_HOST_TRIPLE}"
 else
-    CFG_TARGET_TRIPLES="${CFG_TARGET_TRIPLES/,/ }"
+    CFG_TARGET_TRIPLES="$(echo $CFG_TARGET_TRIPLES | tr ',' ' ')"
 fi
 
 
@@ -459,12 +459,26 @@ do
 	LLVM_CXXFLAGS_32="-m32"
 	LLVM_LDFLAGS_32="-m32"
 
-        # FIXME: Need to change flags for x64
-	LLVM_CXX=$LLVM_CXX_32
-	LLVM_CC=$LLVM_CC_32
-	LLVM_CFLAGS=$LLVM_CFLAGS_32
-	LLVM_CXXFLAGS=$LLVM_CXXFLAGS_32
-	LLVM_LDFLAGS=$LLVM_LDFLAGS_32
+	LLVM_CXX_64="g++"
+	LLVM_CC_64="gcc"
+	LLVM_CFLAGS_64=""
+	LLVM_CXXFLAGS_64=""
+	LLVM_LDFLAGS_64=""
+
+	if echo $t | grep x86_64
+	then
+	    LLVM_CXX=$LLVM_CXX_64
+	    LLVM_CC=$LLVM_CC_64
+	    LLVM_CFLAGS=$LLVM_CFLAGS_64
+	    LLVM_CXXFLAGS=$LLVM_CXXFLAGS_64
+	    LLVM_LDFLAGS=$LLVM_LDFLAGS_64
+	else
+	    LLVM_CXX=$LLVM_CXX_32
+	    LLVM_CC=$LLVM_CC_32
+	    LLVM_CFLAGS=$LLVM_CFLAGS_32
+	    LLVM_CXXFLAGS=$LLVM_CXXFLAGS_32
+	    LLVM_LDFLAGS=$LLVM_LDFLAGS_32
+	fi
 
 	CXX=$LLVM_CXX
 	CC=$LLVM_CC