* gnu/packages/compression.scm (snappy): Update to 1.1.9.
[source]: Add another patch.
[arguments]: Add new #:configure-flags and an
'unpack-third_party-subprojects phase.
[native-inputs]: Add the sources for benchmark and googletests.
* gnu/packages/patches/snappy-add-inline-for-GCC.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
