diff --git a/aclocal.m4 b/aclocal.m4
index 207ef06..cc9811f 100755
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -1237,11 +1237,13 @@ AC_DEFUN(SNERT_TERMIOS,[
 	echo
 	AC_CHECK_HEADERS([termios.h],[
 		AC_CHECK_FUNCS(tcgetattr tcsetattr tcgetwinsize tcsetwinsize ctermid)
+		unset ac_cv_type_struct_winsize
 		AC_CHECK_TYPES([struct winsize],[],[],[
 #include <termios.h>
 		])
 	])
 	AC_CHECK_HEADERS([sys/ioctl.h],[
+		unset ac_cv_type_struct_winsize
 		AC_CHECK_TYPES([struct winsize],[],[],[
 #include <sys/ioctl.h>
 		])
diff --git a/configure b/configure
index e1eef11..80d6080 100755
--- a/configure
+++ b/configure
@@ -8368,6 +8368,7 @@ then :
 
 fi
 
+		unset ac_cv_type_struct_winsize
 		ac_fn_c_check_type "$LINENO" "struct winsize" "ac_cv_type_struct_winsize" "
 #include <termios.h>
 
@@ -8391,6 +8392,7 @@ if test "x$ac_cv_header_sys_ioctl_h" = xyes
 then :
   printf "%s\n" "#define HAVE_SYS_IOCTL_H 1" >>confdefs.h
 
+		unset ac_cv_type_struct_winsize
 		ac_fn_c_check_type "$LINENO" "struct winsize" "ac_cv_type_struct_winsize" "
 #include <sys/ioctl.h>