android-ndk: Use Linux binaries on Linuxbrew
android-ndk: Use Linux binaries on Linuxbrew

The original Homebrew version of this formula uses the prebuilt Darwin
binaries. This patch downloads and unpacks the Linux binaries instead
when we are not on a Mac.

Closes #717.

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

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