Loadable modules with FSF compilers on Darwin MacOS X

[Bill Northcott]

There is a problem building loadable modules on Darwin/MacOS X using  
libtool and FSF compilers.

A typical build failure looks like this:
> /bin/sh ../../../libtool --tag=CXX --mode=link /usr/local/gcc4.0/ 
> bin/g++  -g -O2   -o basefunctions.la -rpath /usr/local/lib/jags/ 
> modules -no-undefined -module -avoid-version basefunctions_la- 
> Add.lo basefunctions_la-Divide.lo basefunctions_la-Equals.lo  
> basefunctions_la-Multiply.lo basefunctions_la-Neg.lo  
> basefunctions_la-Pow.lo basefunctions_la-Subtract.lo  
> basefunctions_la-module.lo ../../../src/lib/libjags.la -lm
> /usr/local/gcc4.0/bin/g++  -o .libs/basefunctions.so -bundle  .libs/ 
> basefunctions_la-Add.o .libs/basefunctions_la-Divide.o .libs/ 
> basefunctions_la-Equals.o .libs/basefunctions_la-Multiply.o .libs/ 
> basefunctions_la-Neg.o .libs/basefunctions_la-Pow.o .libs/ 
> basefunctions_la-Subtract.o .libs/basefunctions_la- 
> module.o  ../../../src/lib/.libs/libjags.dylib -lm
> i686-apple-darwin8-g++-4.0.3: couldn't run '/usr/local/gcc4.0/bin/ 
> undle-gcc-4.0.3': No such file or directory

There is always some complaint about a missing file or directory  
whose name starts with 'undle'.

The immediate cause can be seen in the g++ command above where '- 
bundle' is the second option.  Unless -bundle is the first option on  
the command line, it is interpreted as '-b undle' which causes the  
errors.

In the package concerned the cause seems to be around line 220 of the  
configured libtool where one finds:
> module_cmds="\$CC \$allow_undefined_flag -o \$lib -bundle \$libobjs  
> \$deplibs\$compiler_flags"
> module_expsym_cmds="sed -e \\\"s,#.*,,\\\" -e \\\"s,^[    ]*,,\\\" - 
> e \\\"s,^\\\\(..*\\\\),_&,\\\" < \$export_symbols > \$output_objdir/ 
> \${libname}-symbols.expsym~\$CC \$allow_undefined_flag  -o \$lib - 
> bundle \$libobjs \$deplibs\$compiler_flags~nmedit -s \ 
> $output_objdir/\${libname}-symbols.expsym \${lib}"

Of course it is easy enough to rearrange those lines and get it to  
build, but it seems to me like a bug in libtool.  Alternatively, it  
is a bug in the compiler, although I think it is documented somewhere.

The version here is 1.5.22 on MacOS X 10.4.10 Intel using the gcc  
compilers distributed with R-2.4.1.

Using Apple's compilers there does not seem to be the same issue  
maybe they require -b to be followed by a space.

I know I am not the only one to hit this problem.

Bill Northcott