LU-12269 build: fix hardened builds in rpm spec file

LU-12269 build: fix hardened builds in rpm spec file

The hardened build configure on RHEL8 has a quoted string
with spaces in it, and this breaks the construction of
%eval_configure on lustre.spec.in - the quotes end up in
the wrong place.

Moreover, the hardened build flags are only for user-space
code, and breaks kernel code compilation on RHEL 8.0 (it
adds -fPIE, which isn't valid for kernel code.

This patch stores the %build_cflags and %build_ldflags from
rpmbuild as environment variables before turning hardened
build off to allow the kernel code to build. These
environment variables are used in the lnet/utils and
lustre/utils Makefiles so that the user-space code there
gets the benefit of any system-specific RPM build flag
(such as hardened builds).

For RHEL7 on PPC64 we then also need to define the C macro
__SANE_USERSPACE_TYPES__ so that __s64 and __u64 are long
long instead of the default long - otherwise the build will
fail with a format string error on this platform because
Lustre uses %ll when printing/scanning __s64/__u64.

The environment variables (UTILS_CFLAGS and UTILS_LDFLAGS)
could also be used for a standalone, non-RPM build to pass
flags to the user-space code, with the usual CFLAGS and
LDFLAGS still used for kernel code.

This patch is back-ported from the following one:
Lustre-commit: 5270583ae6e436e9e7ae0199312e7f50365744af
Lustre-change: https://review.whamcloud.com/34882

Signed-off-by: Ben Menadue <ben.menadue@anu.edu.au>
Change-Id: I9b4ba830bf63838fd88ef1bae5dd10dff2109a1d
Reviewed-by: Minh Diep <mdiep@whamcloud.com>
Reviewed-by: Li Dongyang <dongyangli@ddn.com>
Reviewed-on: https://review.whamcloud.com/35161
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Yang Sheng <ys@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>