package/libcgroup: fix build with BR2_TIME_BITS_64

Do not remove _FILE_OFFSET_BITS=64 from CFLAGS and CPPFLAGS to avoid the
following build failure with BR2_TIME_BITS_64 raised since commit
3c427c6472:

In file included from /home/fabrice/buildroot/output/host/mips-buildroot-linux-gnu/sysroot/usr/include/features.h:394,
                 from ../include/libcgroup/error.h:9,
                 from ../include/libcgroup.h:21,
                 from log.c:15:
/home/fabrice/buildroot/output/host/mips-buildroot-linux-gnu/sysroot/usr/include/features-time64.h:26:5: error: #error "_TIME_BITS=64 is allowed only with _FILE_OFFSET_BITS=64"
   26 | #   error "_TIME_BITS=64 is allowed only with _FILE_OFFSET_BITS=64"
      |     ^~~~~

Indeed, this LFS workaround is there since the addition of the package
in commit ff7191c12e and is only needed to
fix a build failure with the old codesourcery-arm toolchain from 2014
which uses glibc < 2.23. as glibc 2.23 was released in February 2016:
https://sourceware.org/glibc/wiki/Release/2.23, drop this workaround as
already done for libselinux in commit
c1fa9bc2f7. A follow-up patch will also
drop codesourcery-arm toolchain.

Fixes: 3c427c6472
 - No autobuilder failures (yet)

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libcgroup/libcgroup.mk

@@ -12,13 +12,6 @@ LIBCGROUP_CPE_ID_VALID = YES
 LIBCGROUP_DEPENDENCIES = host-bison host-flex
 LIBCGROUP_INSTALL_STAGING = YES
 
-# Undefining _FILE_OFFSET_BITS here because of a "bug" with glibc fts.h
-# large file support. See https://bugzilla.redhat.com/show_bug.cgi?id=574992
-# for more information.
-LIBCGROUP_CONF_ENV = \
-	CXXFLAGS="$(TARGET_CXXFLAGS) -U_FILE_OFFSET_BITS" \
-	CFLAGS="$(TARGET_CFLAGS) -U_FILE_OFFSET_BITS"
-
 LIBCGROUP_CONF_OPTS = \
 	--disable-daemon \
 	--disable-initscript-install