[Ffmpeg-devel] ffmpeg compile fail w/gcc 3.4.3 due to lrintf definition (revisited)

[Robert Lippmann]

hi all,

i figured out the problem.  turns out the have_lrintf test fails in
configure when i was using a library not on the system (specifically
via --enable-dts).  extralibs winds up being set "-lm -ldts", which of
course fails to compile.

this is the only test where extralibs is used in a compile test.  it causes
problems in gcc 3.4 because it's trying to optimize by file (ie static
functions) and gets confused with having 2 definitions of lrintf, one static
and one not.  older versions of gcc probably didn't care, but doing forward,
it might be a problem.

a suggestion might be to have a system_extralibs that's set based upon the
system type checks (i.e. -lm, -lsocket, etc), and use that value for the
lrintf test.  the system_extralibs can be added to the end of extralibs.

this way, stupid end users like me will see that the enabled library is
missing at compile time, rather than try to figure out why there's lrintf
problems.

if not, well, then, at least i documented this for posterity :)

-- rob