Preloading in ltdl doesn't heed libname_spec.

[Peter Rosin]

Hi!

When you open libfoo.la, the preloader assumes that the preloaded
library is named libfoo.$libext. I.e. it doesn't care about the
libname_spec variable. This patch fixes that and makes
lt_dladvise.at pass on MSYS/MSVC (and maybe on OS/2).

Cheers,
Peter

2009-11-24  Peter Rosin  <p...@lysator.liu.se>

        Make preloading heed libname_spec.
        * libltdl/ltdl.c (libprefix): New static variable describing
        the prefix of static archives.
        (try_dlopen): Use libprefix.
        * libltdl/m4/ltdl.m4 (_LTDL_SETUP): Export prefix of static
        archives to config.h.

diff --git a/libltdl/ltdl.c b/libltdl/ltdl.c
index 6e19599..28ffc8a 100644
--- a/libltdl/ltdl.c
+++ b/libltdl/ltdl.c
@@ -54,6 +54,10 @@ or obtained by writing to the Free Software Foundation, Inc.,
 #  define LT_LIBEXT "a"
 #endif
 
+#if !defined(LT_LIBPREFIX)
+#  define LT_LIBPREFIX "lib"
+#endif
+
 /* This is the maximum symbol size that won't require malloc/free */
 #undef LT_SYMBOL_LENGTH
 #define LT_SYMBOL_LENGTH       128
@@ -72,6 +76,7 @@ or obtained by writing to the Free Software Foundation, Inc.,
 static const char      objdir[]                = LT_OBJDIR;
 static const char      archive_ext[]           = LT_ARCHIVE_EXT;
 static  const char     libext[]                = LT_LIBEXT;
+static  const char     libprefix[]             = LT_LIBPREFIX;
 #if defined(LT_MODULE_EXT)
 static const char      shlib_ext[]             = LT_MODULE_EXT;
 #endif
@@ -1263,8 +1268,8 @@ try_dlopen (lt_dlhandle *phandle, const char *filename, 
const char *ext,
 
       if (vtable)
        {
-         /* name + "." + libext + NULL */
-         archive_name = MALLOC (char, LT_STRLEN (name) + LT_STRLEN (libext) + 
2);
+         /* libprefix + name + "." + libext + NULL */
+         archive_name = MALLOC (char, LT_STRLEN (libprefix) + LT_STRLEN (name) 
+ LT_STRLEN (libext) + 2);
          *phandle = (lt_dlhandle) lt__zalloc (sizeof (struct lt__handle));
 
          if ((*phandle == NULL) || (archive_name == NULL))
@@ -1276,7 +1281,14 @@ try_dlopen (lt_dlhandle *phandle, const char *filename, 
const char *ext,
 
          /* Preloaded modules are always named according to their old
             archive name.  */
-         sprintf (archive_name, "%s.%s", name, libext);
+         if (strncmp(name, "lib", 3) == 0)
+           {
+             sprintf (archive_name, "%s%s.%s", libprefix, name + 3, libext);
+           }
+         else
+           {
+             sprintf (archive_name, "%s.%s", name, libext);
+           }
 
          if (tryall_dlopen (&newhandle, archive_name, advise, vtable) == 0)
            {
diff --git a/libltdl/m4/ltdl.m4 b/libltdl/m4/ltdl.m4
index 111fac1..2b9bd06 100644
--- a/libltdl/m4/ltdl.m4
+++ b/libltdl/m4/ltdl.m4
@@ -410,6 +410,11 @@ AC_CHECK_FUNCS([strlcat strlcpy], [], 
[AC_LIBOBJ([lt__strl])])
 m4_pattern_allow([LT_LIBEXT])dnl
 AC_DEFINE_UNQUOTED([LT_LIBEXT],["$libext"],[The archive extension])
 
+name=
+lt_libprefix=`eval "\\$ECHO \"$libname_spec\""`
+m4_pattern_allow([LT_LIBPREFIX])dnl
+AC_DEFINE_UNQUOTED([LT_LIBPREFIX],["$lt_libprefix"],[The archive prefix])
+
 name=ltdl
 LTDLOPEN=`eval "\\$ECHO \"$libname_spec\""`
 AC_SUBST([LTDLOPEN])