gradle: add 1.7-rc1 as --devel

Added gradle 1.7-rc-1 install under devel switch

Closes #21086.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
libgpg-error 1.12

Closes #21083.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
libassuan 2.1.1

Closes #21082.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
webp 0.3.1, add webp-mux flags

Closes #21080.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
knock 0.6

* Update formula for changes in build scripts
* Avoid installing the man page for a binary we don't include

Closes #21056.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
doxygen: llvm requires option for --with-libclang

Fixes #21090.