[libc++] Remove _LIBCPP_HAS_NO_FGETPOS_FSETPOS (#72073)

Instead of using individual macros to turn off missing C library
features, we use the using_if_exists attribute now. This patch removes
the _LIBCPP_HAS_NO_FGETPOS_FSETPOS macro used to workaround missing
fgetpos and fsetpos on older versions of Android -- using_if_exists
should take care of those in the headers and we should add appropriate
XFAILs to the tests instead of using TEST_HAS_NO_FGETPOS_FSETPOS.

Author: ldionne

libcxx/include/__config

@@ -1344,13 +1344,6 @@ __sanitizer_verify_double_ended_contiguous_container(const void*, const void*, c
 #    define _LIBCPP_FOPEN_CLOEXEC_MODE
 #  endif
 
-// Support for _FILE_OFFSET_BITS=64 landed gradually in Android, so the full set
-// of functions used in cstdio may not be available for low API levels when
-// using 64-bit file offsets on LP32.
-#  if defined(__BIONIC__) && defined(__USE_FILE_OFFSET64) && __ANDROID_API__ < 24
-#    define _LIBCPP_HAS_NO_FGETPOS_FSETPOS
-#  endif
-
 #  if __has_attribute(__init_priority__)
 #    define _LIBCPP_INIT_PRIORITY_MAX __attribute__((__init_priority__(100)))
 #  else

libcxx/include/cstdio

@@ -141,13 +141,9 @@ using ::putc _LIBCPP_USING_IF_EXISTS;
 using ::ungetc _LIBCPP_USING_IF_EXISTS;
 using ::fread _LIBCPP_USING_IF_EXISTS;
 using ::fwrite _LIBCPP_USING_IF_EXISTS;
-#ifndef _LIBCPP_HAS_NO_FGETPOS_FSETPOS
 using ::fgetpos _LIBCPP_USING_IF_EXISTS;
-#endif
 using ::fseek _LIBCPP_USING_IF_EXISTS;
-#ifndef _LIBCPP_HAS_NO_FGETPOS_FSETPOS
 using ::fsetpos _LIBCPP_USING_IF_EXISTS;
-#endif
 using ::ftell _LIBCPP_USING_IF_EXISTS;
 using ::rewind _LIBCPP_USING_IF_EXISTS;
 using ::clearerr _LIBCPP_USING_IF_EXISTS;

libcxx/test/libcxx/depr/depr.c.headers/no_fgetpos_fsetpos.verify.cpp

@@ -161,13 +161,9 @@ ASSERT_SAME_TYPE(int,    decltype(puts("")));
 ASSERT_SAME_TYPE(int,    decltype(ungetc(0,fp)));
 ASSERT_SAME_TYPE(size_t, decltype(fread((void*)0,0,0,fp)));
 ASSERT_SAME_TYPE(size_t, decltype(fwrite((const void*)arr,1,0,fp)));
-#ifndef TEST_HAS_NO_FGETPOS_FSETPOS
 ASSERT_SAME_TYPE(int,    decltype(fgetpos(fp, &fpos)));
-#endif
 ASSERT_SAME_TYPE(int,    decltype(fseek(fp, 0,0)));
-#ifndef TEST_HAS_NO_FGETPOS_FSETPOS
 ASSERT_SAME_TYPE(int,    decltype(fsetpos(fp, &fpos)));
-#endif
 ASSERT_SAME_TYPE(long,   decltype(ftell(fp)));
 ASSERT_SAME_TYPE(void,   decltype(rewind(fp)));
 ASSERT_SAME_TYPE(void,   decltype(clearerr(fp)));

libcxx/test/std/depr/depr.c.headers/stdio_h.compile.pass.cpp

@@ -126,13 +126,9 @@ int main(int, char**)
     static_assert((std::is_same<decltype(std::ungetc(0,fp)), int>::value), "");
     static_assert((std::is_same<decltype(std::fread((void*)0,0,0,fp)), std::size_t>::value), "");
     static_assert((std::is_same<decltype(std::fwrite(vp,0,0,fp)), std::size_t>::value), "");
-#ifndef TEST_HAS_NO_FGETPOS_FSETPOS
     static_assert((std::is_same<decltype(std::fgetpos(fp, &fpos)), int>::value), "");
-#endif
     static_assert((std::is_same<decltype(std::fseek(fp, 0,0)), int>::value), "");
-#ifndef TEST_HAS_NO_FGETPOS_FSETPOS
     static_assert((std::is_same<decltype(std::fsetpos(fp, &fpos)), int>::value), "");
-#endif
     static_assert((std::is_same<decltype(std::ftell(fp)), long>::value), "");
     static_assert((std::is_same<decltype(std::rewind(fp)), void>::value), "");
     static_assert((std::is_same<decltype(std::clearerr(fp)), void>::value), "");

libcxx/test/std/input.output/file.streams/c.files/cstdio.pass.cpp

@@ -390,10 +390,6 @@ inline void DoNotOptimize(Tp const& value) {
 #  define TEST_HAS_NO_FILESYSTEM
 #endif
 
-#if defined(_LIBCPP_HAS_NO_FGETPOS_FSETPOS)
-#  define TEST_HAS_NO_FGETPOS_FSETPOS
-#endif
-
 #if defined(_LIBCPP_HAS_NO_C8RTOMB_MBRTOC8)
 #  define TEST_HAS_NO_C8RTOMB_MBRTOC8
 #endif