I thought I'd try this on a Mac to see whether it was different.
gc-7.6.0 came without libatomic_ops but tried to use it.
cc -O -I./include -I./libatomic_ops/src -DGC_ATOMIC_UNCOLLECTABLE -DNO_EXECUTE_PERMISSION -DALL_INTERIOR_POINTERS -c -o fnlz_mlc.o fnlz_mlc.c
make: *** No rule to make target `libatomic_ops/src/atomic_ops.c', needed by `atomic_ops.o'. Stop.
I went back to the web site and followed the instructions:
% mkdir gc.d
% cd gc.d
% git clone git://github.com/ivmai/libatomic_ops.git
% git clone git://github.com/ivmai/bdwgc.git
% ln -s libatomic_ops/ bdwgc/libatomic_ops
% cd bdwgc
% autoreconf -vif
% automake --add-missing
% ./configure --prefix=$HOME/local
checking for sys/dg_sys_info.h... no
./configure: line 17050: syntax error near unexpected token `ATOMIC_OPS,'
./configure: line 17050: ` PKG_CHECK_MODULES(ATOMIC_OPS, atomic_ops, ,'
# Note: "syntax error near unexpected token ATOMIC_OPS" reported by configure
# means Autotools pkg.m4 file was not found during aclocal.m4 generation.
if test x"$with_libatomic_ops" != xno; then :
PKG_CHECK_MODULES(ATOMIC_OPS, atomic_ops, ,
I haven't the least idea what to do about this, so I am unable to compare the
Linux result with the OSX result, sorry.