ghostscript: Fix for Linuxbrew
ghostscript: Fix for Linuxbrew

Closes #779.

Signed-off-by: Shaun Jackman <b580dab3251a9622aba3803114310c23fdb42900@gmail.com>

sjackman/linuxbrew,Homebrew/linuxbrew,Angeldude/linuxbrew,drbenmorgan/linuxbrew,Homebrew/linuxbrew,Linuxbrew/linuxbrew,ebouaziz/linuxbrew,DoomHammer/linuxbrew,DoomHammer/linuxbrew,gnubila-france/linuxbrew,reelsense/linuxbrew,Linuxbrew/linuxbrew,Angeldude/linuxbrew,ebouaziz/linuxbrew,bukzor/linuxbrew,SuperNEMO-DBD/cadfaelbrew,drbenmorgan/linuxbrew,bukzor/linuxbrew,reelsense/linuxbrew,DoomHammer/linuxbrew,ebouaziz/linuxbrew,sjackman/linuxbrew,sjackman/linuxbrew,Linuxbrew/linuxbrew,saketkc/linuxbrew,ebouaziz/linuxbrew,bukzor/linuxbrew,saketkc/linuxbrew,SuperNEMO-DBD/cadfaelbrew,SuperNEMO-DBD/cadfaelbrew,Linuxbrew/linuxbrew,Angeldude/linuxbrew,bukzor/linuxbrew,gnubila-france/linuxbrew,reelsense/linuxbrew,Homebrew/linuxbrew,DoomHammer/linuxbrew,gnubila-france/linuxbrew,drbenmorgan/linuxbrew,gnubila-france/linuxbrew,Homebrew/linuxbrew,drbenmorgan/linuxbrew,Angeldude/linuxbrew,SuperNEMO-DBD/cadfaelbrew,reelsense/linuxbrew,saketkc/linuxbrew,saketkc/linuxbrew,sjackman/linuxbrew