[PATCH v6 00/13] 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.

These patches will need to be merged in one shot to avoid 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 12 Makefiles.

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:
 - 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.


Edward Liaw (13):
  selftests/mm: Define _GNU_SOURCE to an empty string
  selftests: Add -D_GNU_SOURCE= to CFLAGS in lib.mk
  selftests/net: Append to lib.mk CFLAGS in Makefile
  selftests/exec: Drop redundant -D_GNU_SOURCE CFLAGS in Makefile
  selftests/futex: Drop redundant -D_GNU_SOURCE CFLAGS in Makefile
  selftests/intel_pstate: Drop redundant -D_GNU_SOURCE CFLAGS in
    Makefile
  selftests/iommu: Drop redundant -D_GNU_SOURCE CFLAGS in Makefile
  selftests/kvm: Drop redundant -D_GNU_SOURCE CFLAGS in Makefile
  selftests/proc: Drop redundant -D_GNU_SOURCE CFLAGS in Makefile
  selftests/resctrl: Drop redundant -D_GNU_SOURCE CFLAGS in Makefile
  selftests/ring-buffer: Drop redundant -D_GNU_SOURCE CFLAGS in Makefile
  selftests/riscv: Drop redundant -D_GNU_SOURCE CFLAGS in Makefile
  selftests/sgx: Append CFLAGS from lib.mk to HOST_CFLAGS

 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 +-
 14 files changed, 12 insertions(+), 14 deletions(-)

--
2.45.2.741.gdbec12cfda-goog