[3.13] reinstate _OPTIMIZED & LTO_CFLAGS for correct flag handling in install_base.sh

[h-vetinari]

Fix-up for #902 (same as #914), because the following code actually requires _OPTIMIZED to be set

python-feedstock/recipe/install_base.sh

Lines 40 to 59 in 28c6e49

	declare -a _FLAGS_REPLACE=()
	if [[ ${_OPTIMIZED} == yes ]]; then
	_FLAGS_REPLACE+=(-O3)
	_FLAGS_REPLACE+=(-O2)
	_FLAGS_REPLACE+=("-fprofile-use")
	_FLAGS_REPLACE+=("")
	_FLAGS_REPLACE+=("-fprofile-correction")
	_FLAGS_REPLACE+=("")
	_FLAGS_REPLACE+=("-L.")
	_FLAGS_REPLACE+=("")
	for _LTO_CFLAG in "${LTO_CFLAGS[@]}"; do
	_FLAGS_REPLACE+=(${_LTO_CFLAG})
	_FLAGS_REPLACE+=("")
	done
	fi
	SYSCONFIG=$(find ${_buildd_static}/$(cat ${_buildd_static}/pybuilddir.txt) -name "_sysconfigdata*.py" -print0)
	cat ${SYSCONFIG} | ${SYS_PYTHON} "${RECIPE_DIR}"/replace-word-pairs.py \
	"${_FLAGS_REPLACE[@]}" \
	> ${PREFIX}/lib/python${VERABI_NO_DBG}/$(basename ${SYSCONFIG})

[conda-forge-admin]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe/meta.yaml) and found it was in an excellent condition.

I do have some suggestions for making it better though...

For recipe/meta.yaml:

• ℹ️ The recipe is not parsable by parser conda-souschef (grayskull). This parser is not currently used by conda-forge, but may be in the future. We are collecting information to see which recipes are compatible with grayskull.
• ℹ️ The recipe is not parsable by parser conda-recipe-manager. The recipe can only be automatically migrated to the new v1 format if it is parseable by conda-recipe-manager.

_{This message was generated by GitHub Actions workflow run https://github.com/conda-forge/conda-forge-webservices/actions/runs/33570514128. Examine the logs at this URL for more detail.}

[yhlee-tw]

@isuruf

I think this introduced a regression in the Linux 3.13 build.

With 3.13.15-hf47f18c_102_cp313, sysconfig contains the invalid -partition=none flag, while the other LTO-related flags are still present:

$ python -c 'import sysconfig; print(sysconfig.get_config_var("CFLAGS"))'
-fno-strict-overflow -Wsign-compare -DNDEBUG -O2 -Wall -fPIC -O2 -fno-merge-constants -isystem /opt/conda/envs/test/include -fdebug-prefix-map=/home/conda/feedstock_root/build_artifacts/python-split_1788361500653/work=/usr/local/src/conda/python-split-3.13.15 -fuse-linker-plugin -ffat-lto-objects -partition=none -fPIC -O2 -fno-merge-constants -isystem /opt/conda/envs/test/include -fdebug-prefix-map=/home/conda/feedstock_root/build_artifacts/python-split_1788361500653/work=/usr/local/src/conda/python-split-3.13.15 -fuse-linker-plugin -ffat-lto-objects -partition=none

and pip builds of C extensions fail with:

gcc: error: unrecognized command-line option '-partition=none'

Downgrading to 3.13.15-hf47f18c_101_cp313 fixes the issue; that build still has -O3 and the valid -flto-partition=none.

It looks like the intent here is to rewrite -O3 to -O2 and remove the build-time LTO flags:

-fuse-linker-plugin
-ffat-lto-objects
-flto-partition=none
-flto

In _102, the -O3 -> -O2 rewrite happened, but the LTO cleanup seems to have only partially happened: -fuse-linker-plugin and -ffat-lto-objects are still there, and -flto-partition=none became the invalid -partition=none.

EDIT: now I see the same reported in #914 (comment) (on 3.14) as well as #919 and #920.