all: variable sized options

vlib/os/os.v

@@ -798,12 +798,17 @@ pub fn get_raw_stdin() []byte {
 			for {
 				pos := buf + offset
 				res := C.ReadFile(h_input, pos, block_bytes, &bytes_read, 0)
+				offset += bytes_read
+
 				if !res {
 					break
 				}
-				offset += bytes_read
+
 				buf = v_realloc(buf, offset + block_bytes + (block_bytes-bytes_read))
 			}
+
+			C.CloseHandle(h_input)
+
 			return array{element_size: 1 data: voidptr(buf) len: offset cap: offset }
 		}
 	} $else {

vlib/os/os_nix.c.v

@@ -154,3 +154,7 @@ pub fn (mut f File) close() {
 	C.fflush(f.cfile)
 	C.fclose(f.cfile)
 }
+
+pub fn debugger_present() bool {
+	return false
+}

vlib/os/os_windows.c.v

@@ -345,4 +345,11 @@ pub type VectoredExceptionHandler fn(&ExceptionPointers)u32
 
 pub fn add_vectored_exception_handler(first bool, handler VectoredExceptionHandler) {
 	C.AddVectoredExceptionHandler(u32(first), handler)
-}
+}
+
+// this is defined in builtin_windows.c.v in builtin
+// fn C.IsDebuggerPresent() bool
+
+pub fn debugger_present() bool {
+	return C.IsDebuggerPresent()
+}