dante: disable sched_getscheduler() - not implemented in musl

musl doesn't come with an valid implementation of `sched_getscheduler()`;
it simply returns -ENOSYS for it. Without this option (and compile dante
with `sched_getscheduler()` enabled), you will get

    error: serverinit(): sched_getscheduler(2): failed to retrieve current
    cpuscheduling policy: Function not implemented

and dante won't start at all.

Ref: http://lists.alpinelinux.org/alpine-devel/3932.html
Ref: http://lists.alpinelinux.org/alpine-devel/3936.html
Signed-off-by: David Yang <mmyangfl@gmail.com>
[slightly reword commit message]
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

package/network/utils/dante/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=dante
 PKG_VERSION:=1.4.1
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=http://www.inet.no/dante/files/
@@ -29,7 +29,8 @@ CONFIGURE_ARGS += \
 	--disable-libwrap
 
 CONFIGURE_VARS += \
-	ac_cv_search_pam_start=""
+	ac_cv_search_pam_start="" \
+	ac_cv_func_sched_setscheduler=no
 
 define Build/InstallDev
 	$(INSTALL_DIR) $(1)/usr/include