diff --git a/libc/config/linux/riscv64/entrypoints.txt b/libc/config/linux/riscv64/entrypoints.txt
--- a/libc/config/linux/riscv64/entrypoints.txt
+++ b/libc/config/linux/riscv64/entrypoints.txt
@@ -477,6 +477,8 @@
     # unistd.h entrypoints
     libc.src.unistd.environ
     libc.src.unistd.execv
+    libc.src.unistd.fork
+    libc.src.unistd.__llvm_libc_syscall
     libc.src.unistd.getopt
     libc.src.unistd.optarg
     libc.src.unistd.optind
diff --git a/libc/src/unistd/linux/fork.cpp b/libc/src/unistd/linux/fork.cpp
--- a/libc/src/unistd/linux/fork.cpp
+++ b/libc/src/unistd/linux/fork.cpp
@@ -14,6 +14,7 @@
 #include "src/__support/threads/thread.h" // For thread self object
 
 #include "src/errno/libc_errno.h"
+#include <signal.h>      // For SIGCHLD
 #include <sys/syscall.h> // For syscall numbers.
 
 namespace __llvm_libc {
diff --git a/libc/test/src/unistd/syscall_test.cpp b/libc/test/src/unistd/syscall_test.cpp
--- a/libc/test/src/unistd/syscall_test.cpp
+++ b/libc/test/src/unistd/syscall_test.cpp
@@ -36,15 +36,33 @@
   constexpr const char LINK_VAL[] = "syscall_readlink_test_value";
   constexpr const char LINK[] = "testdata/syscall_readlink.test.link";
 
+#ifdef SYS_symlink
   ASSERT_GE(__llvm_libc::syscall(SYS_symlink, LINK_VAL, LINK), 0l);
+#elif defined(SYS_symlinkat)
+  ASSERT_GE(__llvm_libc::syscall(SYS_symlinkat, LINK_VAL, AT_FDCWD, LINK), 0l);
+#else
+#error "Symlink syscalls not available."
+#endif
   ASSERT_EQ(libc_errno, 0);
 
   char buf[sizeof(LINK_VAL)];
 
+#ifdef SYS_readlink
   ASSERT_GE(__llvm_libc::syscall(SYS_readlink, LINK, buf, sizeof(buf)), 0l);
+#elif defined(SYS_readlinkat)
+  ASSERT_GE(
+      __llvm_libc::syscall(SYS_readlinkat, AT_FDCWD, LINK, buf, sizeof(buf)),
+      0l);
+#endif
   ASSERT_EQ(libc_errno, 0);
 
+#ifdef SYS_unlink
   ASSERT_GE(__llvm_libc::syscall(SYS_unlink, LINK), 0l);
+#elif defined(SYS_unlinkat)
+  ASSERT_GE(__llvm_libc::syscall(SYS_unlinkat, AT_FDCWD, LINK, 0), 0l);
+#else
+#error "Unlink syscalls not available."
+#endif
   ASSERT_EQ(libc_errno, 0);
 }
 
@@ -54,8 +72,15 @@
 
   constexpr const char *TEST_FILE = "testdata/syscall_pread_pwrite.test";
 
+#ifdef SYS_open
   int fd =
       __llvm_libc::syscall(SYS_open, TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
+#elif defined(SYS_openat)
+  int fd = __llvm_libc::syscall(SYS_openat, AT_FDCWD, TEST_FILE,
+                                O_WRONLY | O_CREAT, S_IRWXU);
+#else
+#error "Open syscalls not available to available."
+#endif
   ASSERT_GT(fd, 0);
   ASSERT_EQ(libc_errno, 0);
 
@@ -83,15 +108,29 @@
   //   3. Open the link to check that the link was created.
   //   4. Cleanup the file and its link.
 
+#ifdef SYS_open
   int write_fd = __llvm_libc::syscall(SYS_open, TEST_FILE_PATH,
                                       O_WRONLY | O_CREAT, S_IRWXU);
+#elif defined(SYS_openat)
+  int write_fd = __llvm_libc::syscall(SYS_openat, AT_FDCWD, TEST_FILE_PATH,
+                                      O_WRONLY | O_CREAT, S_IRWXU);
+#else
+#error "Open syscalls not available to available."
+#endif
   ASSERT_GT(write_fd, 0);
   ASSERT_EQ(libc_errno, 0);
 
   ASSERT_GE(__llvm_libc::syscall(SYS_close, write_fd), 0l);
   ASSERT_EQ(libc_errno, 0);
 
+#ifdef SYS_open
   int dir_fd = __llvm_libc::syscall(SYS_open, TEST_DIR, O_DIRECTORY, 0);
+#elif defined(SYS_openat)
+  int dir_fd =
+      __llvm_libc::syscall(SYS_openat, AT_FDCWD, TEST_DIR, O_DIRECTORY, 0);
+#else
+#error "Open syscalls not available to available."
+#endif
   ASSERT_GT(dir_fd, 0);
   ASSERT_EQ(libc_errno, 0);
 
@@ -99,15 +138,35 @@
                                  TEST_FILE_LINK, 0),
             0l);
   ASSERT_EQ(libc_errno, 0);
-
+#ifdef SYS_open
   int link_fd = __llvm_libc::syscall(SYS_open, TEST_FILE_LINK_PATH, O_PATH, 0);
+#elif defined(SYS_openat)
+  int link_fd = __llvm_libc::syscall(SYS_openat, AT_FDCWD, TEST_FILE_LINK_PATH,
+                                     O_PATH, 0);
+#else
+#error "Open syscalls not available to available."
+#endif
   ASSERT_GT(link_fd, 0);
   ASSERT_EQ(libc_errno, 0);
 
+#ifdef SYS_unlink
   ASSERT_GE(__llvm_libc::syscall(SYS_unlink, TEST_FILE_PATH), 0l);
+#elif defined(SYS_unlinkat)
+  ASSERT_GE(__llvm_libc::syscall(SYS_unlinkat, AT_FDCWD, TEST_FILE_PATH, 0),
+            0l);
+#else
+#error "Unlink syscalls not available."
+#endif
   ASSERT_EQ(libc_errno, 0);
 
+#ifdef SYS_unlink
   ASSERT_GE(__llvm_libc::syscall(SYS_unlink, TEST_FILE_LINK_PATH), 0l);
+#elif defined(SYS_unlinkat)
+  ASSERT_GE(
+      __llvm_libc::syscall(SYS_unlinkat, AT_FDCWD, TEST_FILE_LINK_PATH, 0), 0l);
+#else
+#error "Unlink syscalls not available."
+#endif
   ASSERT_EQ(libc_errno, 0);
 
   ASSERT_GE(__llvm_libc::syscall(SYS_close, dir_fd), 0l);