[Bug modula2/107612] plugin/m2rte doesn't build on Mac OS X 10.7

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107612

--- Comment #11 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Iain D Sandoe <iains@gcc.gnu.org>:

https://gcc.gnu.org/g:ebc41f9a817dbae01c7450cd33c1968318ce8df0

commit r13-4939-gebc41f9a817dbae01c7450cd33c1968318ce8df0
Author: Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>
Date:   Thu Dec 15 10:43:37 2022 +0000

    modula-2: Fix building the plugin for Darwin [PR107612].

     * Makes the configured value for INCINTL available as a variable so that
    it can be used in language makefile fragements.  It is then used in the m2
    fragment to make the include path available to the plugin compile.

     * Updates the DSO suffix  to use .dylib for Darwin.

     * Adds '-Wl,-undefined,dynamic_lookup' to the link flags so that symbols
can
       be resolved at runtime.

     * Removes the extraneous $(exeext) from the DSO names.

    Since the linking is driven by CXX, we also need to supress the addition of
    default libraries otherwise:
     (1) we will get a reference to an uninstalled libstdc++
     (2) the process opening the plugin would have two instances 0f libstdc++ -
         one statically linked into gm2 and one dynamically linked into the
plugin.

            PR modula2/107612

    gcc/ChangeLog:

            * Makefile.in: Make the configured libintl includes avaiable in
INCINTL.
            (BUILD_CPPFLAGS): Use INCINTL.

    gcc/m2/ChangeLog:

            * Make-lang.in (soext): Use .dylib for Darwin.
            (PLUGINLDFLAGS): Use dynmic lookup, set the plugin name, and append
            -nodefaultlibs to suppress the linking of libstdc++.
            Use INCINTL in compile lines for the plugin.

    Co-Authored-By: Iain Sandoe <iain@sandoe.co.uk>