doc/filters: fix degrees/radians copy/paste fail.
build: disable iconv by default.

It seems to break a lot on MacOS because of a mixup between multiple
iconv libraries. The issue is that the configure check link with no
particular library path (so it uses /usr/lib/libiconv.dylib where all
the symbols are defined). OTOH, the final build might link with extra
library paths, such as the ports lib directory (typically you get
-L/opt/local/lib because of an extra library such as SDL). Whatever this
option position (before or after -liconv), it will try to link with
/opt/local/lib/libiconv.dylib, and the issue is that this version has
the same symbols as the ones in /usr/lib/libiconv.dylib except that they
all start with 'lib' (libiconv_open, libiconv_close, ...). I don't plan
to try to workaround this mess, so any better solution is welcome.
compat/strtod: isspace -> av_isspace.

This should fix build after 88d55b8.
Add h264chroma dependency for vp5 and vp6 decoder to configure.

Fix building for some unusual configurations.
Add h264qpel dependency for snow codec to configure.

Fix building for some unusual configurations.
Add h264chroma dependency for cavs decoder to configure.

Fix building for some unusual configurations.
buildsys: only include log2_tab per library for shared builds

Fix linking failures with -all_load due to multiple log2_tabs

Signed-off-by: Carl Eugen Hoyos <cehoyos@ag.or.at>
build: [autodetect] -> [no] in iconv help.
Merge remote-tracking branch 'cehoyos/master'

* cehoyos/master:
  buildsys: only include log2_tab per library for shared builds
  Add h264chroma dependency for cavs decoder to configure.
  Add h264qpel dependency for snow codec to configure.
  Add h264chroma dependency for vp5 and vp6 decoder to configure.

Merged-by: Michael Niedermayer <michaelni@gmx.at>