Problem with release build.

[sanjayss via Digitalmars-d-learn]

In the following sample program (which tries to set terminal to 
raw mode and check for key presses), compiling as usual (dmd 
t.d), the program works, but compiling in release mode (dmd 
-release t.d) and the raw mode doesn't seem to work. Where do I 
start looking to figure this out or if it is obvious, what am I 
doing wrong? (In the release mode output, notice the character 
getting echo-ed before the "Got").

MacBook-Pro:$ dmd --version
DMD64 D Compiler v2.069.2
Copyright (c) 1999-2015 by Digital Mars written by Walter Bright
MacBook-Pro:$ dmd t.d
MacBook-Pro:$ ./t
Got: a
Got: b
Got: c
Got: d
Got: q
MacBook-Pro:$ dmd -release t.d
MacBook-Pro:$ ./t
aGot: a
bGot: b
cGot: c
dGot: d
eGot: e
qGot: q
MacBook-Pro:$ cat t.d
import core.thread;
import core.stdc.stdio;
import core.sys.posix.fcntl;
import core.sys.posix.termios;
import std.stdio : writeln;
int oldf;
termios oldt;

void
makeraw()
{
    termios newt;

    assert(tcgetattr(0, &oldt) == 0);
    newt = oldt;

    newt.c_lflag &= ~(ICANON | ECHO | ECHONL | ISIG | IEXTEN);
    newt.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | ICRNL | 
IGNCR | IXON | IXOFF);
    newt.c_cc[VMIN] = 1;
    assert(tcsetattr(0, TCSANOW, &newt) == 0);

    oldf = fcntl(0, F_GETFL, 0);
    fcntl(0, F_SETFL, oldf | O_NONBLOCK);
}

void
makecooked()
{
    fcntl(0, F_SETFL, oldf);
    assert(tcsetattr(0, TCSANOW, &oldt) == 0);
}

void
main(string[] args)
{
    int ch;

    makeraw();
    scope(exit) makecooked();

    do
    {
        while ((ch = fgetc(stdin)) == EOF)
        {
            Thread.sleep(dur!("seconds")(1));
        }
        writeln("Got: ", cast(dchar)ch);
    } while (ch != 'q');
}