heirloom-mailx: run makeconfig in configure step

The heirloom-mailx Makefile runs makeconfig if this has not been done
before.  In a parallel build, this means makeconfig may be run several
times in parallel because there are two targets that depend on makeconfig.
See for instance
http://autobuild.buildroot.net/results/d24854be69961f71db189f9d804d4bd2cfa078da

To avoid this, run makeconfig in the configure step, which is not parallel.

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/heirloom-mailx/heirloom-mailx.mk

@@ -12,6 +12,10 @@ ifeq ($(BR2_PACKAGE_OPENSSL),y)
 HEIRLOOM_MAILX_DEPENDENCIES += openssl
 endif
 
+define HEIRLOOM_MAILX_CONFIGURE_CMDS
+	(cd $(@D); $(TARGET_CONFIGURE_OPTS) $(SHELL) ./makeconfig)
+endef
+
 define HEIRLOOM_MAILX_BUILD_CMDS
 	$(TARGET_CONFIGURE_OPTS) $(MAKE) -C $(@D)
 endef