[PATCH v7 0/1] Centralize _GNU_SOURCE definition into lib.mk

[Edward Liaw <edliaw@google.com>]

Centralizes the definition of _GNU_SOURCE into lib.mk and addresses all
resulting macro redefinition warnings.

The initial attempt at this patch was abandoned because it affected
lines in many source files and caused a large amount of churn. However,
from earlier discussions, centralizing _GNU_SOURCE is still desireable.
This attempt limits the changes to 1 source file and 14 Makefiles.

This is condensed into a single commit to avoid redefinition warnings
from partial merges.

v1: https://lore.kernel.org/linux-kselftest/20240430235057.1351993-1-edliaw@google.com/
v2: https://lore.kernel.org/linux-kselftest/20240507214254.2787305-1-edliaw@google.com/
 - Add -D_GNU_SOURCE to KHDR_INCLUDES so that it is in a single
   location.
 - Remove #define _GNU_SOURCE from source code to resolve redefinition
   warnings.
v3: https://lore.kernel.org/linux-kselftest/20240509200022.253089-1-edliaw@google.com/
 - Rebase onto linux-next 20240508.
 - Split patches by directory.
 - Add -D_GNU_SOURCE directly to CFLAGS in lib.mk.
 - Delete additional _GNU_SOURCE definitions from source code in
   linux-next.
 - Delete additional -D_GNU_SOURCE flags from Makefiles.
v4: https://lore.kernel.org/linux-kselftest/20240510000842.410729-1-edliaw@google.com/
 - Rebase onto linux-next 20240509.
 - Remove Fixes tag from patches that drop _GNU_SOURCE definition.
 - Restore space between comment and includes for selftests/damon.
v5: https://lore.kernel.org/linux-kselftest/20240522005913.3540131-1-edliaw@google.com/
 - Rebase onto linux-next 20240521
 - Drop initial patches that modify KHDR_INCLUDES.
 - Incorporate Mark Brown's patch to replace static_assert with warning.
 - Don't drop #define _GNU_SOURCE from nolibc and wireguard.
 - Change Makefiles for x86 and vDSO to append to CFLAGS.
v6: https://lore.kernel.org/linux-kselftest/20240624232718.1154427-1-edliaw@google.com/
 - Rewrite patch to use -D_GNU_SOURCE= form in lib.mk.
 - Reduce the amount of churn significantly by allowing definition to
   coexist with source code macro defines.
v7:
 - Squash patch into a single commit.

Edward Liaw (1):
  selftests: Centralize -D_GNU_SOURCE= to CFLAGS in lib.mk

 tools/testing/selftests/exec/Makefile             | 1 -
 tools/testing/selftests/futex/functional/Makefile | 2 +-
 tools/testing/selftests/intel_pstate/Makefile     | 2 +-
 tools/testing/selftests/iommu/Makefile            | 2 --
 tools/testing/selftests/kvm/Makefile              | 2 +-
 tools/testing/selftests/lib.mk                    | 3 +++
 tools/testing/selftests/mm/thuge-gen.c            | 2 +-
 tools/testing/selftests/net/Makefile              | 2 +-
 tools/testing/selftests/net/tcp_ao/Makefile       | 2 +-
 tools/testing/selftests/proc/Makefile             | 1 -
 tools/testing/selftests/resctrl/Makefile          | 2 +-
 tools/testing/selftests/ring-buffer/Makefile      | 1 -
 tools/testing/selftests/riscv/mm/Makefile         | 2 +-
 tools/testing/selftests/sgx/Makefile              | 2 +-
 tools/testing/selftests/tmpfs/Makefile            | 1 -
 15 files changed, 12 insertions(+), 15 deletions(-)

--
2.45.2.803.g4e1b14247a-goog