* libvtv/configure.ac : Add ACX_LT_HOST_FLAGS. Define VTV_CYGMIN.
* libvtv/configure.tgt : (x86_64-*-cygwin*, i?86-*-cygwin*,
x86_64-*-mingw*)
- (i?86-*-mingw*): Add to supported targets.
+ (i?86-*-mingw*): Add to supported targets.
* libvtv/vtv_fail.cc : Skip inclusion of execinfo.h on Cygwin and MinGW.
(log_error_message): Skip calls to backtrace and backtrace_symbols_fd
on Cygwin and MinGW.