[libc++][nfc] Add TEST_HAS_NO_FGETPOS_FSETPOS.

This avoids using an libc++ internal macro in our tests.

Reviewed By: #libc, philnik, ldionne

Differential Revision: https://reviews.llvm.org/D119742

Author: mordante

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

@@ -156,11 +156,11 @@ int main(int, char**)
     static_assert((std::is_same<decltype(ungetc(0,fp)), int>::value), "");
     static_assert((std::is_same<decltype(fread((void*)0,0,0,fp)), size_t>::value), "");
     static_assert((std::is_same<decltype(fwrite((const void*)arr,1,0,fp)), size_t>::value), "");
-#ifndef _LIBCPP_HAS_NO_FGETPOS_FSETPOS
+#ifndef TEST_HAS_NO_FGETPOS_FSETPOS
     static_assert((std::is_same<decltype(fgetpos(fp, &fpos)), int>::value), "");
 #endif
     static_assert((std::is_same<decltype(fseek(fp, 0,0)), int>::value), "");
-#ifndef _LIBCPP_HAS_NO_FGETPOS_FSETPOS
+#ifndef TEST_HAS_NO_FGETPOS_FSETPOS
     static_assert((std::is_same<decltype(fsetpos(fp, &fpos)), int>::value), "");
 #endif
     static_assert((std::is_same<decltype(ftell(fp)), long>::value), "");

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

@@ -122,11 +122,11 @@ 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 _LIBCPP_HAS_NO_FGETPOS_FSETPOS
+#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 _LIBCPP_HAS_NO_FGETPOS_FSETPOS
+#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), "");

libcxx/test/support/test_macros.h

@@ -390,6 +390,10 @@ inline void DoNotOptimize(Tp const& value) {
 #  define TEST_HAS_NO_FILESYSTEM_LIBRARY
 #endif
 
+#if defined(_LIBCPP_HAS_NO_FGETPOS_FSETPOS)
+#  define TEST_HAS_NO_FGETPOS_FSETPOS
+#endif
+
 #if defined(__GNUC__)
 #pragma GCC diagnostic pop
 #endif