ANDROID: Quash macro redefinition warnings for mm/thuge-gen

The warnings are caused by macro imports from
sysroot/usr/include/linux/mman.h clashing with macro definitions in
thuge-gen.c.  This seems to be unavoidable because the android headers
cause sys/mman.h to eventually import this header.

Bug: 339526723
Test: tools/bazel build kselftest_tests_x86_64
Signed-off-by: Edward Liaw <edliaw@google.com>
(cherry picked from https://android-review.googlesource.com/q/commit:0d1cacb93363a4fe8ccd09e12215e111da468e06)
Merged-In: Icc49de03c5a6334313e3c72cf01fe794156ca395
Change-Id: Icc49de03c5a6334313e3c72cf01fe794156ca395