diff --git a/snapshot/linux/signal_context.h b/snapshot/linux/signal_context.h
index 89e697a0..a76852e2 100644
--- a/snapshot/linux/signal_context.h
+++ b/snapshot/linux/signal_context.h
@@ -16,11 +16,11 @@
 #define CRASHPAD_SNAPSHOT_LINUX_SNAPSHOT_SIGNAL_CONTEXT_H_
 
 #include <signal.h>
+#include <stddef.h>
 #include <stdint.h>
 #include <sys/types.h>
 #include <sys/ucontext.h>
 
-#include <cstddef>
 #include <type_traits>
 
 #include "build/build_config.h"
diff --git a/util/misc/from_pointer_cast.h b/util/misc/from_pointer_cast.h
index becf08f0..64ed96f7 100644
--- a/util/misc/from_pointer_cast.h
+++ b/util/misc/from_pointer_cast.h
@@ -15,6 +15,7 @@
 #ifndef CRASHPAD_UTIL_MISC_FROM_POINTER_CAST_H_
 #define CRASHPAD_UTIL_MISC_FROM_POINTER_CAST_H_
 
+#include <stddef.h>
 #include <stdint.h>
 
 #include <cstddef>
diff --git a/util/synchronization/semaphore_posix.cc b/util/synchronization/semaphore_posix.cc
index 1aa4a649..ea20d3ca 100644
--- a/util/synchronization/semaphore_posix.cc
+++ b/util/synchronization/semaphore_posix.cc
@@ -15,10 +15,10 @@
 #include "util/synchronization/semaphore.h"
 
 #include <errno.h>
-#include <math.h>
 #include <time.h>
 
 #include <chrono>
+#include <cmath>
 
 #include "base/check_op.h"
 #include "base/logging.h"
@@ -43,7 +43,7 @@ void Semaphore::Wait() {
 bool Semaphore::TimedWait(double seconds) {
   DCHECK_GE(seconds, 0.0);
 
-  if (isinf(seconds)) {
+  if (std::isinf(seconds)) {
     Wait();
     return true;
   }
@@ -81,7 +81,7 @@ void Semaphore::Wait() {
 bool Semaphore::TimedWait(double seconds) {
   DCHECK_GE(seconds, 0.0);
 
-  if (isinf(seconds)) {
+  if (std::isinf(seconds)) {
     Wait();
     return true;
   }