libtool: Add support for netbsdelf

* m4/libtool.m4: Add support for netbsdelf*-gnu.
* m4/ltdl.m4: Append netbsdelf*-gnu to netbsd* occurrences in case
  statements.
diff --git a/m4/libtool.m4 b/m4/libtool.m4
index 03c4106..c75ad3c 100644
--- a/m4/libtool.m4
+++ b/m4/libtool.m4
@@ -2965,6 +2965,18 @@
   dynamic_linker='GNU/Linux ld.so'
   ;;
 
+netbsdelf*-gnu)
+  version_type=linux
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=no
+  hardcode_into_libs=yes
+  dynamic_linker='NetBSD ld.elf_so'
+  ;;
+
 netbsd*)
   version_type=sunos
   need_lib_prefix=no
@@ -3623,7 +3635,7 @@
   lt_cv_deplibs_check_method=pass_all
   ;;
 
-netbsd*)
+netbsd* | netbsdelf*-gnu)
   if echo __ELF__ | $CC -E - | $GREP __ELF__ > /dev/null; then
     lt_cv_deplibs_check_method='match_pattern /lib[[^/]]+(\.so\.[[0-9]]+\.[[0-9]]+|_pic\.a)$'
   else
@@ -4502,7 +4514,7 @@
 	    ;;
 	esac
 	;;
-      netbsd*)
+      netbsd* | netbsdelf*-gnu)
 	;;
       *qnx* | *nto*)
         # QNX uses GNU C++, but need to define -shared option too, otherwise
@@ -5338,7 +5350,7 @@
       fi
       ;;
 
-    netbsd*)
+    netbsd* | netbsdelf*-gnu)
       if echo __ELF__ | $CC -E - | $GREP __ELF__ >/dev/null; then
 	_LT_TAGVAR(archive_cmds, $1)='$LD -Bshareable $libobjs $deplibs $linker_flags -o $lib'
 	wlarc=
@@ -5881,7 +5893,7 @@
       esac
       ;;
 
-    netbsd*)
+    netbsd* | netbsdelf*-gnu)
       if echo __ELF__ | $CC -E - | $GREP __ELF__ >/dev/null; then
 	_LT_TAGVAR(archive_cmds, $1)='$LD -Bshareable -o $lib $libobjs $deplibs $linker_flags'  # a.out
       else
diff --git a/m4/ltdl.m4 b/m4/ltdl.m4
index af24408..8ed76ab 100644
--- a/m4/ltdl.m4
+++ b/m4/ltdl.m4
@@ -495,7 +495,7 @@
     # at 6.2 and later dlopen does load deplibs.
     lt_cv_sys_dlopen_deplibs=yes
     ;;
-  netbsd*)
+  netbsd* | netbsdelf*-gnu)
     lt_cv_sys_dlopen_deplibs=yes
     ;;
   openbsd*)