configure: Move toolchain dependency declarations to a more appropriate place
configure: Split host and target libc detection
Merge commit 'c869fcdeac3b7cd71a852b928902daadeca55685'

* commit 'c869fcdeac3b7cd71a852b928902daadeca55685':
  configure: Move toolchain dependency declarations to a more appropriate place

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge remote-tracking branch 'qatar/master'

* qatar/master:
  configure: Split host and target libc detection

Conflicts:
	configure

Merged-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/ffv1enc: fix use of uninitalized variable in choose_rct_params()

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
ffv1.4: use 2 coefficients for calculating the Y plane in the RCT

0-0.7% improved compression

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