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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug libstdc++/103866] New: AM_PROG_LIBTOOL not compatible with
 GCC_NO_EXECUTABLES
Date: Thu, 30 Dec 2021 11:04:00 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D103866

            Bug ID: 103866
           Summary: AM_PROG_LIBTOOL not compatible with GCC_NO_EXECUTABLES
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: build
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org
  Target Milestone: ---

The libtool setup in the top-level libtool.m4 has this snippet in
LT_SYS_DLOPEN_SELF:

  *)
    AC_CHECK_FUNC([shl_load],
          [lt_cv_dlopen=3D"shl_load"],
      [AC_CHECK_LIB([dld], [shl_load],
            [lt_cv_dlopen=3D"shl_load" lt_cv_dlopen_libs=3D"-ldld"],
        [AC_CHECK_FUNC([dlopen],
              [lt_cv_dlopen=3D"dlopen"],
          [AC_CHECK_LIB([dl], [dlopen],
                [lt_cv_dlopen=3D"dlopen" lt_cv_dlopen_libs=3D"-ldl"],
            [AC_CHECK_LIB([svld], [dlopen],
                  [lt_cv_dlopen=3D"dlopen" lt_cv_dlopen_libs=3D"-lsvld"],
              [AC_CHECK_LIB([dld], [dld_link],
                    [lt_cv_dlopen=3D"dld_link" lt_cv_dlopen_libs=3D"-ldld"])
              ])
            ])
          ])
        ])
      ])
    ;;

This can fail if GCC_NO_EXECUTABLES has been used, e.g. for a mips-none-elf
cross-compiler (see Bug 100057 comment 33, but ignore all the other comments
there).

It looks like --disable-dlopen will avoid that snippet, but should that be
necessary if --disable-shared has been used? If it can't depend on
--disable-shared, is there some other flag we can use to infer that the user
doesn't want/need those checks for a bare metal build?=