configure: Group toolchain options together in help output
copy_block: K&R formatting cosmetics
configure: Support older version of openjpeg1

It should work best for debian stable and people not installing the .pc
file.
armv6: vp8: use explicit labels in motion compensation asm

The integrated arm assembler in clang-503.0.38 (Xcode-5.1) fails
to assemble a branch to 'label + offset' in thumb mode.
doc: Point to the correct, actually maintained gas-preprocessor repo

Signed-off-by: Martin Storsjö <martin@martin.st>
http: Properly initialize icy headers string

The icy_metadata_headers string never gets initialized, so,
during the first call to av_strlcatf() in parse_icy(),
strlen() will be called on a pointer to uninitialized memory.
At best this causes some garbage data to be left at the
start of the string.

By initializing icy_metadata_headers to the empty string, the
first call to strlen() will always return 0, so that data is
appended from the start of the string.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>