Current MinGW+MSYS versions deployed on my Wintel have the libtool [2.4.1-msys ??
I doubt: really only usual libtool-2.4-1-mingw32-bin.tar.lzma ],
GCC 4.8.1.
Before a build of the 2.4.2 [for MinGW - not for MSYS] (i.e. the one for this
report): I already decided to use (even for a build and hence for this build)
the libtool file (in /mingw/bin) with my manual correction: I saw the strange
[for the presence of GCC 4.8.1 deployed] script - working,
but inside it there were 4.5.0 paths instead of 4.8.1 (and this is not strange
for the libtool-2.4-1-mingw32-bin.tar.lzma , but only for the current
MinGW+MSYS).
I almost ignore this hand-made file, but here it is among the attachment.
The build of the 2.4.2 that I mention above was successful, but here the .log -
more important file, of cource - is among the attachment.

(One can see
sys_lib_search_path_spec="c:/tingw/lib/gcc/mingw32/4.8.1 c:/tingw/lib/gcc
c:/tingw/mingw32/lib c:/tingw/lib "
and
compiler_lib_search_dirs="c:/tingw/bin/../lib/gcc/mingw32/4.8.1
c:/tingw/bin/../lib/gcc
c:/tingw/bin/../lib/gcc/mingw32/4.8.1/../../../../mingw32/lib
c:/tingw/bin/../lib/gcc/mingw32/4.8.1/../../.."
in the 312.96KB file of the 2.4.2 build
- the "TinGW" substrings are due to my allusion to tin plague under a frost:/)

Best regards, while you can be giving an advice what a libtool without any
hand-made file must become a mean for my case.