On amd64 systems, shared libraries must be built with -fPIC, otherwise linking will fail:

/usr/lib/gcc/x86_64-pc-linux-gnu/4.6.0/../../../../x86_64-pc-linux-gnu/bin/ld: .libs/cogl-gl.o: relocation R_X86_64_32 against `.rodata.str1.1' can not be used when making a shared object; recompile with -fPIC
.libs/cogl-gl.o: could not read symbols: Bad value
collect2: ld returned 1 exit status

Interestingly, cogl's choice of whether or not by default to build its object files with -fPIC depends on the value of cogl_release_status. Allow me to explain.


Cogl's configure.ac contains several lines like

m4_define([default], [m4_if(cogl_release_status, [git], [yes], [no])])

while ltoptions.m4 (included by aclocal.m4) contains the following code:

# implement the --with-pic flag, and support the `pic-only' and `no-pic'
# LT_INIT options.
# MODE is either `yes' or `no'.  If omitted, it defaults to `both'.
m4_define([_LT_WITH_PIC],
[AC_ARG_WITH([pic],
    [AS_HELP_STRING([--with-pic],
        [try to use only PIC/non-PIC objects @<:@default=use both@:>@])],
    [pic_mode="$withval"],
    [pic_mode=default])

test -z "$pic_mode" && pic_mode=m4_default([$1], [default])

In other words, when cogl_release_status="git", m4 defines default="yes", and so the default value of pic_mode is "yes" (build with -fPIC only).

And when cogl_release_status="snapshot", m4 defines default="no", and so the default value of pic_mode is "no" (build without -fPIC only, which is guaranteed to fail on amd64).


Hence, the cogl-1.7.0 tarball (which has cogl_release_status="snapshot") by default fails to link on 64-bit systems. The default can be overridden (using a --with-pic=yes flag passed to configure), but such behavior is certainly not desirable.