redis and hiredis added to Gentoo Overlay

While I was writing some more code for songride I felt that I should have the latest redis version installed. After running emerge '>=dev-db/redis-2.4.17' I was confronted with the following error message:

Re-emerging redis fails too with:
    LINK redis-benchmark
zmalloc.o: In function `zmalloc':
zmalloc.c:(.text+0x1a): undefined reference to `jmalloc'
zmalloc.c:(.text+0x2c): undefined reference to `jmalloc_usable_size'
zmalloc.o: In function `zcalloc':
zmalloc.c:(.text+0xd2): undefined reference to `jcalloc'
zmalloc.c:(.text+0xe4): undefined reference to `jmalloc_usable_size'
zmalloc.o: In function `zrealloc':
zmalloc.c:(.text+0x1a5): undefined reference to `jmalloc_usable_size'
zmalloc.c:(.text+0x1b5): undefined reference to `jrealloc'
zmalloc.c:(.text+0x1ed): undefined reference to `jmalloc_usable_size'
zmalloc.o: In function `zfree':
zmalloc.c:(.text+0x31b): undefined reference to `jmalloc_usable_size'
zmalloc.c:(.text+0x35f): undefined reference to `jfree'
collect2: ld returned 1 exit status
make[1]:  [redis-benchmark] Error 1
make[1]: Leaving directory `/var/tmp/portage/dev-db/redis-2.4.17/work/redis-2.4.17/src'
make:  [all] Error 2
* ERROR: dev-db/redis-2.4.17 failed (compile phase):
*   emake failed

As I this is a problem affecting all Gentoo installations since the upgrade from jemalloc from 3.1 to 3.2 the Gentoo Bug #444796 was already solved and contained an ebuild for redis-2.4.17 that would install fine. Sadly this ebuild is not yet available in the main portage tree so I added it to my overlay.

Another useful project when using redis is hiredis, a minimalistic C client library for which an ebuild is available in Gentoo Bug #440226 but not in the main portage tree. The ebuild in my overlay contains the modification suggested by alexbr.

Both of these ebuilds are GPLv2 licensed so there was no problem in adding them to the overlay.