Triangles $FGH$ and $JKL$ are graphed in the $xy$-plane. Triangle $FGH$ has vertices $F,G,$ and $H$ at $(-5,-1),(-5,-4),$ and $(-2,-1),$ respectively. Triangle $JKL$ has vertices $J,K,$ and $L$ at $(-5,-1),(-5,-4-q),$ and $(-2-q,-1),$ respectively, where $q$ is a positive constant. If the measure of $\angle G$ is $b^{\circ },$ what is the measure of $\angle L$ ?