package/collectd: Specify FP layout based on endianness

Big-endian CPUs store floating point as big endian (at lest majority
of them do), so, in order for 'network' plugin to work correctly (and
potentially any user of htond() in collectd's codebase),
--with-fp-layout=endianflip as opposed to --with-fp-layout=nothing
needs to be specified during configuration phase.

Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
(cherry picked from commit bdd8475b90)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/collectd/collectd.mk

@@ -24,9 +24,23 @@ COLLECTD_PLUGINS_DISABLE = \
 
 COLLECTD_CONF_ENV += LIBS="-lm"
 
+#
+# NOTE: There's also a third availible setting "intswap", which might
+# be needed on some old ARM hardware (see [2]), but is not being
+# accounted for as per discussion [1]
+#
+# [1] http://lists.busybox.net/pipermail/buildroot/2017-November/206100.html
+# [2] http://lists.busybox.net/pipermail/buildroot/2017-November/206251.html
+#
+ifeq ($(BR2_ENDIAN),"BIG")
+COLLECTD_FP_LAYOUT=endianflip
+else
+COLLECTD_FP_LAYOUT=nothing
+endif
+
 COLLECTD_CONF_OPTS += \
 	--with-nan-emulation \
-	--with-fp-layout=nothing \
+	--with-fp-layout=$(COLLECTD_FP_LAYOUT) \
 	--with-perl-bindings=no \
 	$(foreach p, $(COLLECTD_PLUGINS_DISABLE), --disable-$(p)) \
 	$(if $(BR2_PACKAGE_COLLECTD_AGGREGATION),--enable-aggregation,--disable-aggregation) \