[Bug lto/80717] LTO wrappers segfault if run with absolute path

[theivorytower at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80717

--- Comment #2 from Hao Zhang <theivorytower at gmail dot com> ---
Thank you for your reply. For me basically any arguments with /usr/bin/gcc-ar
fails with segfault, even running /usr/bin/gcc-ar with no additional arguments
at all. 

When I run gcc-ar with gdb (here I don't even need to have the absolute path,
"gdb gcc-ar" fails with segfault), before line 203 of gcc-ar.c, the variable
path.plist consists of the following entries:

{0x6070a0 "/usr/local/sbin/",  0x607010 "/usr/local/bin/", 0x6073c0
"/usr/bin/", 0x607400 "/usr/lib/jvm/default/bin/", 0x607450
"/usr/bin/site_perl/", 0x607490 "/usr/bin/vendor_perl/", 0x6074d0
"/usr/bin/core_perl/"}

After line 203, /usr/bin/ is removed from the list of paths:

{0x6070a0 "/usr/local/sbin/",  0x607010 "/usr/local/bin/", 0x0 , 0x607400
"/usr/lib/jvm/default/bin/", 0x607450 "/usr/bin/site_perl/", 0x607490
"/usr/bin/vendor_perl/", 0x6074d0 "/usr/bin/core_perl/"}

Since the third item is set to 0, strcpy segfaults at file-find.c:81.