diff --git a/package/libmicrohttpd/libmicrohttpd.mk b/package/libmicrohttpd/libmicrohttpd.mk
index c53676f520..2266d3ceaa 100644
--- a/package/libmicrohttpd/libmicrohttpd.mk
+++ b/package/libmicrohttpd/libmicrohttpd.mk
@@ -9,7 +9,17 @@ LIBMICROHTTPD_SITE = $(BR2_GNU_MIRROR)/libmicrohttpd
 LIBMICROHTTPD_LICENSE_FILES = COPYING
 LIBMICROHTTPD_INSTALL_STAGING = YES
 LIBMICROHTTPD_CONF_OPTS = --disable-curl --disable-examples
-LIBMICROHTTPD_CONF_ENV += CFLAGS="$(TARGET_CFLAGS) -std=c99"
+LIBMICROHTTPD_CFLAGS = $(TARGET_CFLAGS) -std=c99
+
+# gcc on arc and bfin doesn't define _REENTRANT when -pthread is
+# passed while it should. Compensate this defiency here otherwise
+# libmicrohttpd configure script doesn't find that thread support is
+# enabled.
+ifeq ($(BR2_arc)$(BR2_bfin),y)
+LIBMICROHTTPD_CFLAGS += -D_REENTRANT
+endif
+
+LIBMICROHTTPD_CONF_ENV += CFLAGS="$(LIBMICROHTTPD_CFLAGS)"
 
 ifeq ($(BR2_PACKAGE_LIBMICROHTTPD_SSL),y)
 LIBMICROHTTPD_LICENSE = LGPLv2.1+