package/libcgroup: allow to build with musl and uClibc

libcgroup depends on fts API which is missing in musl and uClibc
and provided by musl-fts package.

This patch makes libcgroup dependent on musl-fts for
non-glibc configurations.

Signed-off-by: Oleg Lyovin <ovlevin@sberdevices.ru>
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>

package/libcgroup/Config.in

@@ -1,8 +1,7 @@
 config BR2_PACKAGE_LIBCGROUP
 	bool "libcgroup"
 	depends on BR2_INSTALL_LIBSTDCPP
-	# libcgroup uses <fts.h> which is not included by default in uClibc
-	depends on BR2_TOOLCHAIN_USES_GLIBC
+	select BR2_PACKAGE_MUSL_FTS if !BR2_TOOLCHAIN_USES_GLIBC
 	help
 	  libcgroup is a library that abstracts the control
 	  group file system in Linux.
@@ -18,5 +17,5 @@ config BR2_PACKAGE_LIBCGROUP_TOOLS
 
 endif
 
-comment "libcgroup needs a glibc toolchain w/ C++"
-	depends on !BR2_INSTALL_LIBSTDCPP || !BR2_TOOLCHAIN_USES_GLIBC
+comment "libcgroup needs a toolchain w/ C++"
+	depends on !BR2_INSTALL_LIBSTDCPP

package/libcgroup/libcgroup.mk

@@ -36,4 +36,8 @@ else
 LIBCGROUP_CONF_OPTS += --disable-pam
 endif
 
+ifeq ($(BR2_TOOLCHAIN_USES_GLIBC),)
+LIBCGROUP_DEPENDENCIES += musl-fts
+endif
+
 $(eval $(autotools-package))