Fix support for the bfd library

There was a regression: -ldl was not tried to link with the bfd library.

This commit fixes this regression.

Changes

@@ -547,8 +547,8 @@ OCaml 4.10.0
 - #8843, #8841: fix use of off_t on 32-bit systems.
   (Stephen Dolan, report by Richard Jones, review by Xavier Leroy)
 
-- #8947, #9134: fix/improve support for the BFD library
-  (Sébastien Hinderer, review by Damien Doligez)
+- #8947, #9134, #9302: fix/improve support for the BFD library
+  (Sébastien Hinderer, review by Damien Doligez and David Allsopp)
 
 - #8951: let make's default target build the compiler
   (Sébastien Hinderer, review by David Allsopp)

configure

@@ -16083,7 +16083,7 @@ if ${ac_cv_lib_bfd_bfd_openr+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lbfd -liberty $LIBS"
+LIBS="-lbfd -ldl $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -16114,7 +16114,7 @@ fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_bfd_bfd_openr" >&5
 $as_echo "$ac_cv_lib_bfd_bfd_openr" >&6; }
 if test "x$ac_cv_lib_bfd_bfd_openr" = xyes; then :
-  bfd_ldlibs="-lbfd -liberty"
+  bfd_ldlibs="-lbfd -ldl"
 fi
 
 fi
@@ -16126,7 +16126,7 @@ if ${ac_cv_lib_bfd_bfd_openr+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lbfd -liberty -lz $LIBS"
+LIBS="-lbfd -ldl -liberty $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -16157,7 +16157,7 @@ fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_bfd_bfd_openr" >&5
 $as_echo "$ac_cv_lib_bfd_bfd_openr" >&6; }
 if test "x$ac_cv_lib_bfd_bfd_openr" = xyes; then :
-  bfd_ldlibs="-lbfd -liberty -lz"
+  bfd_ldlibs="-lbfd -ldl -liberty"
 fi
 
 fi
@@ -16169,7 +16169,7 @@ if ${ac_cv_lib_bfd_bfd_openr+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lbfd -liberty -lz -lintl $LIBS"
+LIBS="-lbfd -ldl -liberty -lz $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -16200,7 +16200,50 @@ fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_bfd_bfd_openr" >&5
 $as_echo "$ac_cv_lib_bfd_bfd_openr" >&6; }
 if test "x$ac_cv_lib_bfd_bfd_openr" = xyes; then :
-  bfd_ldlibs="-lbfd -liberty -lz -lintl"
+  bfd_ldlibs="-lbfd -ldl -liberty -lz"
+fi
+
+fi
+    if test -z "$bfd_ldlibs"; then :
+  unset ac_cv_lib_bfd_bfd_openr
+      { $as_echo "$as_me:${as_lineno-$LINENO}: checking for bfd_openr in -lbfd" >&5
+$as_echo_n "checking for bfd_openr in -lbfd... " >&6; }
+if ${ac_cv_lib_bfd_bfd_openr+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lbfd -ldl -liberty -lz -lintl $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char bfd_openr ();
+int
+main ()
+{
+return bfd_openr ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_bfd_bfd_openr=yes
+else
+  ac_cv_lib_bfd_bfd_openr=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_bfd_bfd_openr" >&5
+$as_echo "$ac_cv_lib_bfd_bfd_openr" >&6; }
+if test "x$ac_cv_lib_bfd_bfd_openr" = xyes; then :
+  bfd_ldlibs="-lbfd -ldl -liberty -lz -lintl"
 fi
 
 fi

configure.ac

@@ -1516,16 +1516,20 @@ AS_IF([test x"$with_bfd" != "xno"],
     AS_IF([test -z "$bfd_ldlibs"],
       [unset ac_cv_lib_bfd_bfd_openr
       AC_CHECK_LIB([bfd], [bfd_openr],
-        [bfd_ldlibs="-lbfd -liberty"], [], [-liberty])])
+        [bfd_ldlibs="-lbfd -ldl"], [], [-ldl])])
     AS_IF([test -z "$bfd_ldlibs"],
       [unset ac_cv_lib_bfd_bfd_openr
       AC_CHECK_LIB([bfd], [bfd_openr],
-        [bfd_ldlibs="-lbfd -liberty -lz"], [], [-liberty -lz])])
+        [bfd_ldlibs="-lbfd -ldl -liberty"], [], [-ldl -liberty])])
     AS_IF([test -z "$bfd_ldlibs"],
       [unset ac_cv_lib_bfd_bfd_openr
       AC_CHECK_LIB([bfd], [bfd_openr],
-        [bfd_ldlibs="-lbfd -liberty -lz -lintl"], [],
-        [-liberty -lz -lintl])])
+        [bfd_ldlibs="-lbfd -ldl -liberty -lz"], [], [-ldl -liberty -lz])])
+    AS_IF([test -z "$bfd_ldlibs"],
+      [unset ac_cv_lib_bfd_bfd_openr
+      AC_CHECK_LIB([bfd], [bfd_openr],
+        [bfd_ldlibs="-lbfd -ldl -liberty -lz -lintl"], [],
+        [-ldl -liberty -lz -lintl])])
     AS_IF([test -n "$bfd_ldlibs"],
       [bfd_available=true
       AC_DEFINE([HAS_LIBBFD])])])