Linking error with recent libdc

[Gaetan Bisson]

[2015-07-07 20:21:49 -1000] Gaetan Bisson:
> Building subsurface master against that still fails for me.

So things work as expected if I compile libdc without build flags.

Our build system uses:

CPPFLAGS="-D_FORTIFY_SOURCE=2"
CFLAGS="-march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong --param=ssp-buffer-size=4"
CXXFLAGS="-march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong --param=ssp-buffer-size=4"
LDFLAGS="-Wl,-O1,--sort-common,--as-needed,-z,relro"

And apparently one of them makes libdc unhappy... I'll narrow it down
and report back.

-- 
Gaetan