message: build: enforce minimum required Windows version (7)
  Instruct the linker to set the major & minor subsystem versions in the PE
  header to 6 & 1 (NT 6.1 which corresponds to Windows 7). Similar to
  macOS, the binary will now refuse to run on unsupported versions of
  Windows.
diff: @@ -632,6 +632,8 @@ case $host in
  archive_cmds_CXX="\$CC -shared \$libobjs \$deplibs \$compiler_flags -static -o \$output_objdir/\$soname \${wl}--enable-auto-image-base -Xlinker --out-implib -Xlinker \$lib"
  postdeps_CXX=
  + dnl We require Windows 7 (NT 6.1) or later
  + AX_CHECK_LINK_FLAG([[-Wl,--major-subsystem-version -Wl,6 -Wl,--minor-subsystem-version -Wl,1]],[LDFLAGS="$LDFLAGS -Wl,--major-subsystem-version -Wl,6 -Wl,--minor-subsystem-version -Wl,1"],,[[$LDFLAG_WERROR]])
  ;;
  *darwin*)
  TARGET_OS=darwin
  