diff --git a/configure.ac b/configure.ac
index 752673e0..f261614e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -496,7 +496,7 @@ elif test "$assert" = soft; then
 	AC_DEFINE(SOFT_ASSERT, 1, [Define this to enable soft asserts.])
 	AC_DEFINE(NDEBUG, 1, [Define this to disable debugging support.])
 elif test "$assert" = yes; then
-	assert = "hard";
+	assert="hard"
 fi
 
 AC_MSG_CHECKING(if you want to do a profile build)
diff --git a/librb/configure.ac b/librb/configure.ac
index 13b6791a..89ef564d 100644
--- a/librb/configure.ac
+++ b/librb/configure.ac
@@ -404,7 +404,7 @@ elif test "$assert" = soft; then
 	AC_DEFINE(SOFT_ASSERT, 1, [Define this to enable soft asserts.])
 	AC_DEFINE(NDEBUG, 1, [Define this to disable debugging support.])
 elif test "$assert" = yes; then
-	assert = "hard";
+	assert="hard"
 fi
 
 AC_MSG_CHECKING(if you want to do a profile build)