diff --git a/configure.ac b/configure.ac
index 848b0ef01..43d28d7a6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1120,7 +1120,7 @@ AC_TYPE_INTPTR_T
 AC_TYPE_UINTPTR_T
 
 dnl C standard type sizes on this platform
-AC_CHECK_SIZEOF([char])
+RB_CHECK_SIZEOF([char], 1)
 AC_CHECK_SIZEOF([short])
 AC_CHECK_SIZEOF([int])
 AC_CHECK_SIZEOF([float])
diff --git a/tools/m4/ratbox.m4 b/tools/m4/ratbox.m4
index 792e68da1..277ceafba 100644
--- a/tools/m4/ratbox.m4
+++ b/tools/m4/ratbox.m4
@@ -65,3 +65,11 @@ AC_DEFUN([RB_CHK_SYSHEADER],
 		])
 	fi
 ])
+
+AC_DEFUN([RB_CHECK_SIZEOF],
+[
+	AC_CHECK_SIZEOF([$1])
+	if [[ "${ac_cv_sizeof_$1}" != "$2" ]]; then
+		AC_MSG_ERROR([sizeof($1) must be $2 not ${ac_cv_sizeof_$1}. Check config.log for compiler error.])
+	fi
+])