Optimize func_ltwrapper_scriptname to assume a cwrapper.

[Ralf Wildenhues]

The function func_ltwrapper_executable_p is used right before
func_ltwrapper_scriptname a couple of times in ltmain; the latter again
calls the former.  This costs an extra grep.  The only time we don't
call func_ltwrapper_executable_p first is on a just-created wrapper
executable.

So this should be safe.  And the documentation is there already before
the function, too.

Any reasons against committing this?

Thanks,
Ralf

    Optimize func_ltwrapper_scriptname to assume a cwrapper.
    
    * libltdl/config/ltmain.m4sh (func_ltwrapper_scriptname): Do not
    call func_ltwrapper_executable_p again here, this function is
    documented to allow being called with wrapper executables.

diff --git a/libltdl/config/ltmain.m4sh b/libltdl/config/ltmain.m4sh
index b764ab7..cf15ebc 100644
--- a/libltdl/config/ltmain.m4sh
+++ b/libltdl/config/ltmain.m4sh
@@ -519,12 +519,9 @@ func_ltwrapper_executable_p ()
 # temporary ltwrapper_script.
 func_ltwrapper_scriptname ()
 {
-    func_ltwrapper_scriptname_result=""
-    if func_ltwrapper_executable_p "$1"; then
-       func_dirname_and_basename "$1" "" "."
-       func_stripname '' '.exe' "$func_basename_result"
-       
func_ltwrapper_scriptname_result="$func_dirname_result/$objdir/${func_stripname_result}_ltshwrapper"
-    fi
+    func_dirname_and_basename "$1" "" "."
+    func_stripname '' '.exe' "$func_basename_result"
+    
func_ltwrapper_scriptname_result="$func_dirname_result/$objdir/${func_stripname_result}_ltshwrapper"
 }
 
 # func_ltwrapper_p file