diff --git a/configure.ac b/configure.ac
index 010abc8..d7a17f2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -142,32 +142,18 @@ case $host in
  *-mingw*)
 
   if test -z "$host_alias"; then
-
-      # No --host argument was given to 'configure'; therefore $host
-      # was set to a default value based on the build platform.  But
-      # this default value may be wrong if we are building from a
-      # 64-bit MSYS[2] pre-configured to build 32-bit MinGW programs.
-      # Therefore, we'll try to get the right host platform from the
-      # compiler's target.
-
-      AC_MSG_CHECKING([the compiler's target])
-      if test -z "$CC"; then
-	  cc=gcc
-      else
-	  cc=$CC
-      fi
-      cc_target=`$cc -v 2>&1 | sed -n 's/Target: //p'`
-      case "$cc_target" in
-          *-*) host=$cc_target
-	      ;;
-          "") AC_MSG_ERROR([Impossible to obtain $cc compiler target.
-Please explicitly provide --host.])
-              ;;
-	  *) AC_MSG_WARN([Compiler reported non-standard target.
-Defaulting to $host.])
-              ;;
-      esac
-      AC_MSG_RESULT([$host])
+    # No --host argument was given; therefore $host was set to $build.
+    # But this default value is wrong if we are building from MSYS2
+    # 64-bit with the mingw32 shell, or from MSYS2 32-bit with the
+    # mingw64 shell.  So we have to amend $host in those cases.
+    host1=`AS_ECHO $host | sed \
+      -e 's/x86_64-pc-mingw32/i686-pc-mingw32/' \
+      -e 's/i686-pc-mingw64/x86_64-pc-mingw64/'`
+
+    if test "$host1" != "$host"; then
+      host=$host1
+      AC_MSG_WARN([host system type amended to $host])
+    fi
   fi
 
   . $srcdir/nt/mingw-cfg.site