small fix of libtool.m4

Hi there,

this is the first patch i am committing and i hope i’ll do it right, but please be patient with me if something went wrong accidentally.

DESCRIPTION:
So i found that if you’re running ‘./configure’ on a project that depends on libtool, it might happen that the script will end up with the following error: “/bin/rm: cannot remove 'libtoolT': No such file or directory”. I did some research and found the place within libtool.m4 which tries to remove that file and added a ’test -e’ before the call to ‘rm’. that way the file will get removed if it’s there, but no error will occur if not.

CHANGELOG:
* m4/libtool.m4 safely try to remove temporary cfgfile

please find the patch attached to this email. I hope i provided everything that’s necessary to get this one fixed. if i did something wrong or you need some information from me, please contact me.

kind regards
christian