This patch fixes compilation errors when using ccache wrapper:
```
cc1: error: /nix/store/19vvbsjs6l6j0r22albzhysxfvr94imf-ccache-links/lib/gcc/*/*/include-fixed: No such file or directory
```
From the changelog:
```
Version 0.7.80, 2015-11-30
+ Matroska: support of MKVMerge statistics tags (duration frame count,
stream size, bit rate) per track, thanks to ndjamena
+ FLAC: Channel positions, thanks to ndjamena
+ FLAC: difference between detected bit depth and stored bit depth
+ MPEG-TS: if DTVCC transport stream is present and no DTVCC service
descriptor, scan also in the middle of the file in order to detect
more caption services
+ Subtitle frame rate computing if frame count and duration are
available (hidden by default)
+ Subtitles in Matroska: count of elements
+ Matroska, MXF and MP4/MOV: detection of truncated files
+ DTS: difference between ES Matrix and ES Discrete
+ DTS: display ES Matrix or ES Discrete even if HRA or MA is present
+ DTS: difference between DTS-HRA with 96k option and pure DTS-96/24
+ DTS: detection of DTS:X
+ Samples per frame info
+ AC-3: detection of Atmos inside TrueHD
+ Video frame rate: showing precision of 1/1.001 frame rates (e.g.
"23.976 (24000/1001) fps" and "23.976 (23976/1000) fps")
+ MPEG-4/MOV: showing the complete list of compatible brands in the
CodecID field
+ MPEG-4/MOV: Alternate groups
+ MPEG-4/MOV: "Disabled" tag
+ MPEG-4/MOV: "Forced" tag
+ MPEG-4/MOV: showing links between tracks (chapters for, subtitles for,
fallback for)
+ MXF: handling of more acquisition metadata items
+ MXF: Package name
+ AVC: Store method of interlaced content (Interleaved Fields or
Separated Fields)
+ EBUCore: acquisition metadata (Proof of concept, for feedback only)
x Matroska: frame rate detection algorithm revisited, less wrong numbers
are expected
x SDP/Teletext: some pages were sometimes (when present in 2 different
SDP lines) displayed several times
x MPEG-4/MOV: some hint tracks were not displayed
+ Hongkongese language added
+ Option "Full parsing"
```
- Add new service for `clamd`, the ClamAV daemon.
- Replace the old upstart "jobs" section with systemd.services
- Remove unnecessary config options.
- Use `mkEnableOption`
This renames the current openssl to openssl_1_0_1 and defaults
openssl back to openssl_1_0_1 essentially changing nothing currently,
but allowing people to explicitly select openssl_1_0_1 for some software
which needs ABI compatibility to a specific libssl implementation like
binaries (spotify amongst others) and at the same time overriding
openssl to another implementation like libressl.