Revert "Remove redundant feature checks on re-run of CMake config ste…

[dsharlet]

…p (#2084)"

This reverts commit 6a8dee9.

This commit has broken our build, e.g.:

-- Compiling and running to test GNU_POSIX_REGEX
CMake Error at build/linux/armhf/googlebenchmark-source/CMakeLists.txt:330 (message):
  Failed to determine the source files for the regular expression backend


-- Performing Test GNU_POSIX_REGEX -- failed
-- Compile Output: Change Dir: '/__w/XNNPACK/XNNPACK/build/linux/armhf/CMakeFiles/CMakeTmp'

Run Build Command(s): /usr/bin/ninja -v cmTC_0f13b
[1/2] ccache /usr/bin/arm-linux-gnueabihf-g++   -Wall  -Wextra  -Wshadow  -Wfloat-equal  -Wold-style-cast  -Wconversion  -Wformat=2  -Werror  -Wsuggest-override  -pedantic  -pedantic-errors  -fstrict-aliasing  -Wno-deprecated-declarations  -Wno-deprecated  -Wstrict-aliasing  -std=c++17 -o CMakeFiles/cmTC_0f13b.dir/gnu_posix_regex.cpp.o -c /__w/XNNPACK/XNNPACK/build/linux/armhf/googlebenchmark-source/cmake/gnu_posix_regex.cpp
FAILED: CMakeFiles/cmTC_0f13b.dir/gnu_posix_regex.cpp.o 
ccache /usr/bin/arm-linux-gnueabihf-g++   -Wall  -Wextra  -Wshadow  -Wfloat-equal  -Wold-style-cast  -Wconversion  -Wformat=2  -Werror  -Wsuggest-override  -pedantic  -pedantic-errors  -fstrict-aliasing  -Wno-deprecated-declarations  -Wno-deprecated  -Wstrict-aliasing  -std=c++17 -o CMakeFiles/cmTC_0f13b.dir/gnu_posix_regex.cpp.o -c /__w/XNNPACK/XNNPACK/build/linux/armhf/googlebenchmark-source/cmake/gnu_posix_regex.cpp
/__w/XNNPACK/XNNPACK/build/linux/armhf/googlebenchmark-source/cmake/gnu_posix_regex.cpp:1:10: fatal error: gnuregex.h: No such file or directory
    1 | #include <gnuregex.h>
      |          ^~~~~~~~~~~~
compilation terminated.
ninja: build stopped: subcommand failed.


-- Feature POSIX_REGEX already disabled.

(https://github.com/google/XNNPACK/actions/runs/22084382825/job/63815804259)

This seems to affect most (maybe all) of our cross-compiled builds.

I've spent some time trying to fix this, and found some supsicious things (e.g. COMPILE_OUTPUT_VAR incompletely renamed) but unfortunately we don't have a good way to reproduce these cross-compile builds, so it is difficult to debug.

Considering the original commit was only an optimization of the build, I hope it will be acceptable to just revert it. I've verified that reverting this commit repairs our builds when updating this dependency.

This should reopen #2078

[LebedevRI]

That is unfortunate, the old behaviour is annoying.
Thank you!

[dsharlet]

That is unfortunate, the old behaviour is annoying.

I think only the change to CMakeLists.txt is needed to fix the issue, and the change to CXXFeatureCheck.cmake is just a refactor (with probably a bug).