package/ltp-testsuite: 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
3c427c64726560ea1743282a3fdb78f5b28692eb:

configure:5239: /home/autobuild/autobuild/instance-1/output-1/host/bin/mips-buildroot-linux-gnu-gcc -c -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_TIME_BITS=64 -Os -g2 -I/home/autobuild/autobuild/instance-1/output-1/host/bin/../mips-buildroot-linux-gnu/sysroot/usr/include/tirpc  -fno-builtin -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_TIME_BITS=64 conftest.c >&5
In file included from /home/autobuild/autobuild/instance-1/output-1/host/mips-buildroot-linux-gnu/sysroot/usr/include/features.h:394,
                 from /home/autobuild/autobuild/instance-1/output-1/host/mips-buildroot-linux-gnu/sysroot/usr/include/bits/libc-header-start.h:33,
                 from /home/autobuild/autobuild/instance-1/output-1/host/mips-buildroot-linux-gnu/sysroot/usr/include/limits.h:26,
                 from /home/autobuild/autobuild/instance-1/output-1/host/lib/gcc/mips-buildroot-linux-gnu/13.2.0/include/limits.h:205,
                 from /home/autobuild/autobuild/instance-1/output-1/host/lib/gcc/mips-buildroot-linux-gnu/13.2.0/include/syslimits.h:7,
                 from /home/autobuild/autobuild/instance-1/output-1/host/lib/gcc/mips-buildroot-linux-gnu/13.2.0/include/limits.h:34,
                 from conftest.c:12:
/home/autobuild/autobuild/instance-1/output-1/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"
      |     ^~~~~

[...]

checking for /home/autobuild/autobuild/instance-1/output-1/host/bin/mips-buildroot-linux-gnu-gcc options needed to detect all undeclared functions... cannot detect
configure: error: in `/home/autobuild/autobuild/instance-1/output-1/build/ltp-testsuite-20240129':
configure: error: cannot make /home/autobuild/autobuild/instance-1/output-1/host/bin/mips-buildroot-linux-gnu-gcc report undeclared builtins

Indeed, this LFS workaround was added by commit
ca3524ba707126de7284210c00268a8e7ca6379a 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
c1fa9bc2f7a4e5481edf4fce5c03dd45862fe72c. A follow-up patch will also
drop codesourcery-arm toolchain.

Fixes:
 - http://autobuild.buildroot.org/results/d2e75a79bc42b6a9a2b407fd557aca5c7f207d84

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

package/ltp-testsuite/ltp-testsuite.mk

@@ -47,10 +47,7 @@ else
 LTP_TESTSUITE_CONF_ENV += have_numa_headers=no
 endif
 
-# ltp-testsuite uses <fts.h>, which isn't compatible with largefile
-# support.
-LTP_TESTSUITE_CFLAGS = $(filter-out -D_FILE_OFFSET_BITS=64,$(TARGET_CFLAGS))
-LTP_TESTSUITE_CPPFLAGS = $(filter-out -D_FILE_OFFSET_BITS=64,$(TARGET_CPPFLAGS))
+LTP_TESTSUITE_CFLAGS = $(TARGET_CFLAGS)
 LTP_TESTSUITE_LIBS =
 
 ifeq ($(BR2_PACKAGE_LIBTIRPC),y)
@@ -66,7 +63,6 @@ endif
 
 LTP_TESTSUITE_CONF_ENV += \
 	CFLAGS="$(LTP_TESTSUITE_CFLAGS)" \
-	CPPFLAGS="$(LTP_TESTSUITE_CPPFLAGS)" \
 	LIBS="$(LTP_TESTSUITE_LIBS)" \
 	SYSROOT="$(STAGING_DIR)"