[libc] Fix statvfs test case when SYS_statfs64 is used

When SYS_statfs64 is used, struct statfs64 is used instead of struct statfs.
This patch adds a define to select the appropriate struct, similar to
how it's done internally.

This patch also enables fstatvfs and statvfs on riscv, where these are
failing to compile without this change.

Author: mikhailramalho

libc/config/linux/riscv/entrypoints.txt

@@ -266,6 +266,10 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.sys.stat.mkdirat
     libc.src.sys.stat.stat
 
+    # sys/statvfs.h
+    libc.src.sys.statvfs.fstatvfs
+    libc.src.sys.statvfs.statvfs
+
     # sys/utsname.h entrypoints
     libc.src.sys.utsname.uname
 

libc/config/linux/riscv/headers.txt

@@ -44,6 +44,7 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.sys_select
     libc.include.sys_socket
     libc.include.sys_stat
+    libc.include.sys_statvfs
     libc.include.sys_syscall
     libc.include.sys_time
     libc.include.sys_types

libc/test/src/sys/statvfs/linux/fstatvfs_test.cpp

@@ -9,10 +9,16 @@
 #include <linux/magic.h>
 using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
 
+#ifdef SYS_statfs64
+using statFs = struct statfs64;
+#else
+using statFs = struct statfs;
+#endif
+
 namespace LIBC_NAMESPACE_DECL {
-static int fstatfs(int fd, struct statfs *buf) {
+static int fstatfs(int fd, statFs *buf) {
   using namespace statfs_utils;
-  if (cpp::optional<LinuxStatFs> result = linux_fstatfs(fd)) {
+  if (cpp::optional<statFs> result = linux_fstatfs(fd)) {
     *buf = *result;
     return 0;
   }
@@ -29,7 +35,7 @@ struct PathFD {
 };
 
 TEST(LlvmLibcSysStatvfsTest, FstatfsBasic) {
-  struct statfs buf;
+  statFs buf;
   ASSERT_THAT(LIBC_NAMESPACE::fstatfs(PathFD("/"), &buf), Succeeds());
   ASSERT_THAT(LIBC_NAMESPACE::fstatfs(PathFD("/proc"), &buf), Succeeds());
   ASSERT_EQ(buf.f_type, static_cast<decltype(buf.f_type)>(PROC_SUPER_MAGIC));

libc/test/src/sys/statvfs/linux/statvfs_test.cpp

@@ -6,8 +6,14 @@
 #include <linux/magic.h>
 using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
 
+#ifdef SYS_statfs64
+using statFs = struct statfs64;
+#else
+using statFs = struct statfs;
+#endif
+
 namespace LIBC_NAMESPACE_DECL {
-static int statfs(const char *path, struct statfs *buf) {
+static int statfs(const char *path, statFs *buf) {
   using namespace statfs_utils;
   if (cpp::optional<LinuxStatFs> result = linux_statfs(path)) {
     *buf = *result;
@@ -18,7 +24,7 @@ static int statfs(const char *path, struct statfs *buf) {
 } // namespace LIBC_NAMESPACE_DECL
 
 TEST(LlvmLibcSysStatfsTest, StatfsBasic) {
-  struct statfs buf;
+  statFs buf;
   ASSERT_THAT(LIBC_NAMESPACE::statfs("/", &buf), Succeeds());
   ASSERT_THAT(LIBC_NAMESPACE::statfs("/proc", &buf), Succeeds());
   ASSERT_EQ(buf.f_type, static_cast<decltype(buf.f_type)>(PROC_SUPER_MAGIC));