Replace own dummy syscall with standard library syscall

This makes it easier to support other standard library packages.

README.markdown

@@ -97,10 +97,9 @@ Implemented compiler passes:
 
 Requirements:
 
-  * Go 1.10+ (Go 1.9 has a
+  * Go 1.11+
-    [known bug](https://github.com/aykevl/tinygo/issues/2)).
   * LLVM dependencies, see the Software section in the
-    [LLVM build guide](https://llvm.org/docs/GettingStarted.html#software).
+    [LLVM build guide](https://llvm.org/docs/GettingStarted.html#software)
 
 First download the sources (this takes a while):
 

compiler.go

@@ -1321,6 +1321,11 @@ func (c *Compiler) parseBuiltin(frame *Frame, args []ssa.Value, callName string)
 }
 
 func (c *Compiler) parseFunctionCall(frame *Frame, args []ssa.Value, llvmFn llvm.Value, blocking bool, parentHandle llvm.Value) (llvm.Value, error) {
+	if llvmFn.Name() == "sync.runtime_registerPoolCleanup" || llvmFn.Name() == "sync.runtime_notifyListCheck" {
+		// Ignore these functions calls for now, as a hack.
+		// TODO: implement //go:linkname.
+		return llvm.Value{}, nil
+	}
 	var params []llvm.Value
 	if blocking {
 		if parentHandle.IsNil() {

interpreter.go

@@ -67,6 +67,16 @@ func (p *Program) interpret(instrs []ssa.Instruction, paramKeys []*ssa.Parameter
 			if callee == nil {
 				return i, nil // don't understand dynamic dispatch
 			}
+			if callee.String() == "syscall.runtime_envs" {
+				// TODO: replace this with some //go:linkname magic.
+				// For now, do as if it returned a zero-length slice.
+				var err error
+				locals[instr], err = p.getZeroValue(callee.Signature.Results().At(0).Type())
+				if err != nil {
+					return i, err
+				}
+				continue
+			}
 			if canInterpret(callee) {
 				params := make([]Value, len(common.Args))
 				for i, arg := range common.Args {

src/syscall/syscall.go

@@ -1,5 +0,0 @@
-package syscall
-
-// dummy
-
-type Errno uintptr