Re: Automake 1.5 linker selection

[Christian Cornelssen]

Dear Automake maintainers,

on 26 Nov 2001, Alexandre Duret-Lutz wrote:

> The linker is selected on a per-target basis.  Finding
> AC_LANG(C++) in configure.ac does not mean all the targets in
> your package use C++.
>
> You'd rather override the linker in this particuliar case.
> Grep the documentation for `maude_LINK'.

Thanks.  I have provided a specific linker definition now.

Before submitting my problem report, I have taken a closer look at the
generated `Makefile.in', in order to find tweakable variable
definitions.  Thereby, I encountered another point about the linker
definitions which I want to mention here: Automake 1.5 uses (with
libtool support)

    CCLD = $(CC)
    LINK = $(LIBTOOL) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \
        $(AM_LDFLAGS) $(LDFLAGS) -o $@

    CXXLD = $(CXX)
    CXXLINK = $(LIBTOOL) --mode=link $(CXXLD) $(AM_CXXFLAGS) $(CXXFLAGS) \
        $(AM_LDFLAGS) $(LDFLAGS) -o $@

However, $(CFLAGS) and $(CXXFLAGS) make sense only for $(CC) and
$(CXX), respectively.  If the setting CCLD = $(CC) is meant to allow
easy overriding (with CCLD=$(CXX) or even CCLD=ld, for example), then
the $(...CFLAGS)  stuff can make the $(LINK) command unusable. I
suggest changing the partition of the link command definitions to the
following:

    CCLD = $(CC) $(AM_CFLAGS) $(CFLAGS)
    LINK = $(LIBTOOL) --mode=link $(CCLD) \
        $(AM_LDFLAGS) $(LDFLAGS) -o $@

    CXXLD = $(CXX) $(AM_CXXFLAGS) $(CXXFLAGS)
    CXXLINK = $(LIBTOOL) --mode=link $(CXXLD) \
        $(AM_LDFLAGS) $(LDFLAGS) -o $@

Similar considerations might apply to other compiler/linker
definitions (without libtool, or with fortran, etc.)

Sincerely,

Christian Cornelssen