[libc++] Make LIBCXX_ENABLE_FILESYSTEM fully consistent
Previously, LIBCXX_ENABLE_FILESYSTEM controlled only whether the filesystem
support was compiled into libc++'s library. This commit promotes the
setting to a first-class option like LIBCXX_ENABLE_LOCALIZATION, where
the whole library is aware of the setting and features that depend on
<filesystem> won't be provided at all. The test suite is also properly
annotated such that tests that depend on <filesystem> are disabled when
the library doesn't support it.
This is an alternative to https://llvm.org/D94824, but also an improvement
along the lines of LIBCXX_ENABLE_LOCALIZATION that I had been wanting to
make for a while.
Differential Revision: https://reviews.llvm.org/D94921
diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
index 46a6695..6a55245 100644
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -845,6 +845,7 @@
config_define_if(LIBCXX_HAS_MUSL_LIBC _LIBCPP_HAS_MUSL_LIBC)
config_define_if(LIBCXX_NO_VCRUNTIME _LIBCPP_NO_VCRUNTIME)
config_define_if(LIBCXX_ENABLE_PARALLEL_ALGORITHMS _LIBCPP_HAS_PARALLEL_ALGORITHMS)
+config_define_if_not(LIBCXX_ENABLE_FILESYSTEM _LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
config_define_if_not(LIBCXX_ENABLE_RANDOM_DEVICE _LIBCPP_HAS_NO_RANDOM_DEVICE)
config_define_if_not(LIBCXX_ENABLE_LOCALIZATION _LIBCPP_HAS_NO_LOCALIZATION)
config_define_if_not(LIBCXX_ENABLE_VENDOR_AVAILABILITY_ANNOTATIONS _LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS)
