libtool: add -os2dllname option.

On OS/2, if there are many DLLs whose prefix is the same and
very long, the resulting DLLs are overwritten. Provide a new
option to force a DLL name.
* build-aux/ltmain.in (func_mode_help): Add a description for
-os2dllname.
(func_mode_link): Add -os2dllname.
* doc/libtool.texi: Document it.
* NEWS: Update.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>

NEWS

@@ -24,6 +24,9 @@ NEWS - list of user-visible changes between releases of GNU Libtool
 
        ./configure CC=tcc LD=tcc
 
+  - Added -os2dllname option to work around 8 character base name
+    limit on OS/2.  The option has no effect on other systems.
+
 
 * Noteworthy changes in release 2.4.3 (2014-10-27) [stable]
 

build-aux/ltmain.in

@@ -1818,7 +1818,8 @@ The following components of LINK-COMMAND are treated specially:
   -no-install       link a not-installable executable
   -no-undefined     declare that a library does not refer to external symbols
   -o OUTPUT-FILE    create OUTPUT-FILE from the specified objects
-  -objectlist FILE  Use a list of object files found in FILE to specify objects
+  -objectlist FILE  use a list of object files found in FILE to specify objects
+  -os2dllname NAME  force a short DLL name on OS/2 (no effect on other OSes)
   -precious-files-regex REGEX
                     don't remove output files matching REGEX
   -release RELEASE  specify package release information
@@ -4606,6 +4607,7 @@ func_mode_link ()
     module=no
     no_install=no
     objs=
+    os2dllname=
     non_pic_objects=
     precious_files_regex=
     prefer_static_libs=no
@@ -4863,6 +4865,11 @@ func_mode_link ()
 	  prev=
 	  continue
 	  ;;
+	os2dllname)
+	  os2dllname=$arg
+	  prev=
+	  continue
+	  ;;
 	precious_regex)
 	  precious_files_regex=$arg
 	  prev=
@@ -5172,6 +5179,11 @@ func_mode_link ()
 	continue
 	;;
 
+      -os2dllname)
+	prev=os2dllname
+	continue
+	;;
+
       -o) prev=output ;;
 
       -precious-files-regex)

doc/libtool.texi

@@ -1531,6 +1531,10 @@ Create @var{output-file} from the specified objects and libraries.
 @item -objectlist @var{file}
 Use a list of object files found in @var{file} to specify objects.
 
+@item -os2dllname @var{name}
+Use this to change the DLL base name on OS/2 to @var{name}, to keep
+within the 8 character base name limit on this system.
+
 @item -precious-files-regex @var{regex}
 Prevents removal of files from the temporary output directory whose
 names match this regular expression.  You might specify @samp{\.bbg?$}

m4/libtool.m4

@@ -2811,7 +2811,7 @@ os2*)
   shrext_cmds=.dll
   need_lib_prefix=no
   # OS/2 can only load a DLL with a base name of 8 characters or less.
-  soname_spec='`eval $ECHO $libname | cut -b -8 | tr . _`$shared_ext'
+  soname_spec='`test -n "$os2dllname" && libname=$os2dllname; $ECHO $libname | cut -b -8 | tr . _`$shared_ext'
   library_names_spec='${libname}_dll.$libext'
   dynamic_linker='OS/2 ld.exe'
   shlibpath_var=BEGINLIBPATH