Minimize the $L^1$-norm with linear equality constrain

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How can I solve efficiently the problem:

$$\min_x \| A x \|_1 \quad \text{subject to} \; {b}^{T} x = c$$

for $A \in \mathbb{R}^{m \times n}, b \in \mathbb{R}^{n}, c \in \mathbb{R}$. The matrix $A$ has independent columns.

Is there a closed form solution? Or a trick to quickly calculate $x$?

I am aware it can be solved iteratively by projected gradient descent and by other alternating methods. Yet they converge pretty slowsly.