--- a/compiler-rt/lib/esan/esan_sideline_linux.cpp
+++ b/compiler-rt/lib/esan/esan_sideline_linux.cpp
@@ -70,7 +70,7 @@ int SidelineThread::runSideline(void *Arg) {

   // Set up a signal handler on an alternate stack for safety.
   InternalScopedBuffer<char> StackMap(SigAltStackSize);
-  struct sigaltstack SigAltStack;
+  stack_t SigAltStack;
   SigAltStack.ss_sp = StackMap.data();
   SigAltStack.ss_size = SigAltStackSize;
   SigAltStack.ss_flags = 0;
--- a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cc
@@ -607,8 +607,7 @@ uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5) {
 }
 #endif

-uptr internal_sigaltstack(const struct sigaltstack *ss,
-                         struct sigaltstack *oss) {
+uptr internal_sigaltstack(const void *ss, void *oss) {
   return internal_syscall(SYSCALL(sigaltstack), (uptr)ss, (uptr)oss);
 }

--- a/compiler-rt/lib/sanitizer_common/sanitizer_linux.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux.h
@@ -21,7 +21,6 @@
 #include "sanitizer_platform_limits_posix.h"

 struct link_map;  // Opaque type returned by dlopen().
-struct sigaltstack;

 namespace __sanitizer {
 // Dirent structure for getdents(). Note that this structure is different from
@@ -30,8 +29,7 @@ struct linux_dirent;

 // Syscall wrappers.
 uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count);
-uptr internal_sigaltstack(const struct sigaltstack* ss,
-                          struct sigaltstack* oss);
+uptr internal_sigaltstack(const void* ss, void* oss);
 uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
     __sanitizer_sigset_t *oldset);

--- a/compiler-rt/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc
@@ -273,7 +273,7 @@ static int TracerThread(void* argument) {

   // Alternate stack for signal handling.
   InternalScopedBuffer<char> handler_stack_memory(kHandlerStackSize);
-  struct sigaltstack handler_stack;
+  stack_t handler_stack;
   internal_memset(&handler_stack, 0, sizeof(handler_stack));
   handler_stack.ss_sp = handler_stack_memory.data();
   handler_stack.ss_size = kHandlerStackSize;
--- a/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cc
+++ b/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cc
@@ -282,7 +282,7 @@ void InitializePlatform() {
 int ExtractResolvFDs(void *state, int *fds, int nfd) {
 #if SANITIZER_LINUX && !SANITIZER_ANDROID
   int cnt = 0;
-  __res_state *statp = (__res_state*)state;
+  struct __res_state *statp = (struct __res_state*)state;
   for (int i = 0; i < MAXNS && cnt < nfd; i++) {
     if (statp->_u._ext.nsaddrs[i] && statp->_u._ext.nssocks[i] != -1)
       fds[cnt++] = statp->_u._ext.nssocks[i];
--- a/libcxx/include/__locale
+++ b/libcxx/include/__locale
@@ -34,7 +34,7 @@
 # include <support/solaris/xlocale.h>
 #elif defined(_NEWLIB_VERSION)
 # include <support/newlib/xlocale.h>
-#elif (defined(__GLIBC__) || defined(__APPLE__)      || defined(__FreeBSD__) \
+#elif (defined(__APPLE__)      || defined(__FreeBSD__) \
     || defined(__EMSCRIPTEN__) || defined(__IBMCPP__))
 # include <xlocale.h>
 #elif defined(_LIBCPP_HAS_MUSL_LIBC)