diff --git a/package/htop/htop.mk b/package/htop/htop.mk
index f4d9032d4a..cb8170a0a3 100644
--- a/package/htop/htop.mk
+++ b/package/htop/htop.mk
@@ -13,6 +13,10 @@ HTOP_CONF_ENV = HTOP_NCURSES_CONFIG_SCRIPT=$(STAGING_DIR)/usr/bin/$(NCURSES_CONF
 HTOP_LICENSE = GPL-2.0+
 HTOP_LICENSE_FILES = COPYING
 
+# ac_cv_prog_cc_c99 is required for BR2_USE_WCHAR=n because the C99 test
+# provided by autoconf relies on wchar_t.
+HTOP_CONF_ENV += ac_cv_prog_cc_c99=-std=gnu99
+
 ifeq ($(BR2_PACKAGE_HWLOC),y)
 HTOP_CONF_OPTS += --enable-hwloc
 HTOP_DEPENDENCIES += hwloc