Macron accent (a bar over the letter) in LaTeX not working

Question

I have the following .tex:

\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc} % Required for accented characters

\`{o}  \'{o}  \^{o}  \"{o}  \H{o}  \~{o}  \c{c}  \k{a}  \l{}  \={o}  \b{o}   \.{o}   \d{u}  \r{a}  \u{o}  \v{s} \t{oo}  \o

which after using pdflatex produces the following::

i.e. \={o} and \b{o} aren't producing the bars above and below the o and \v{s} is doing nothing.

What's going on here?!