--- tools/toolutil/toolutil.cpp.orig	2019-10-03 07:30:54.000000000 +1000
+++ tools/toolutil/toolutil.cpp	2019-10-22 03:07:00.000000000 +1100
@@ -60,6 +60,8 @@
 
 #include <errno.h>
 
+#include <cstddef>
+
 #include "unicode/errorcode.h"
 #include "unicode/putil.h"
 #include "cmemory.h"
@@ -243,7 +245,7 @@ struct UToolMemory {
     char name[64];
     int32_t capacity, maxCapacity, size, idx;
     void *array;
-    alignas(max_align_t) char staticArray[1];
+    alignas(std::max_align_t) char staticArray[1];
 };
 
 U_CAPI UToolMemory * U_EXPORT2
--- common/uarrsort.cpp.orig	2019-10-03 07:30:54.000000000 +1000
+++ common/uarrsort.cpp	2019-10-22 03:10:45.000000000 +1100
@@ -18,6 +18,8 @@
 *   Internal function for sorting arrays.
 */
 
+#include <cstddef>
+
 #include "unicode/utypes.h"
 #include "cmemory.h"
 #include "uarrsort.h"
@@ -35,7 +37,7 @@ enum {
 };
 
 static constexpr int32_t sizeInMaxAlignTs(int32_t sizeInBytes) {
-    return (sizeInBytes + sizeof(max_align_t) - 1) / sizeof(max_align_t);
+    return (sizeInBytes + sizeof(std::max_align_t) - 1) / sizeof(std::max_align_t);
 }
 
 /* UComparator convenience implementations ---------------------------------- */
@@ -139,7 +141,7 @@ static void
 insertionSort(char *array, int32_t length, int32_t itemSize,
               UComparator *cmp, const void *context, UErrorCode *pErrorCode) {
 
-    icu::MaybeStackArray<max_align_t, sizeInMaxAlignTs(STACK_ITEM_SIZE)> v;
+    icu::MaybeStackArray<std::max_align_t, sizeInMaxAlignTs(STACK_ITEM_SIZE)> v;
     if (sizeInMaxAlignTs(itemSize) > v.getCapacity() &&
             v.resize(sizeInMaxAlignTs(itemSize)) == nullptr) {
         *pErrorCode = U_MEMORY_ALLOCATION_ERROR;
@@ -233,7 +235,7 @@ static void
 quickSort(char *array, int32_t length, int32_t itemSize,
             UComparator *cmp, const void *context, UErrorCode *pErrorCode) {
     /* allocate two intermediate item variables (x and w) */
-    icu::MaybeStackArray<max_align_t, sizeInMaxAlignTs(STACK_ITEM_SIZE) * 2> xw;
+    icu::MaybeStackArray<std::max_align_t, sizeInMaxAlignTs(STACK_ITEM_SIZE) * 2> xw;
     if(sizeInMaxAlignTs(itemSize)*2 > xw.getCapacity() &&
             xw.resize(sizeInMaxAlignTs(itemSize) * 2) == nullptr) {
         *pErrorCode=U_MEMORY_ALLOCATION_ERROR;
--- common/utext.cpp.orig	2019-10-03 07:30:54.000000000 +1000
+++ common/utext.cpp	2019-10-22 03:13:50.000000000 +1100
@@ -16,6 +16,8 @@
 *   created by: Markus W. Scherer
 */
 
+#include <cstddef>
+
 #include "unicode/utypes.h"
 #include "unicode/ustring.h"
 #include "unicode/unistr.h"
@@ -566,8 +568,8 @@ enum {
 //    when a provider asks for a UText to be allocated with extra storage.
 
 struct ExtendedUText {
-    UText          ut;
-    max_align_t    extension;
+    UText               ut;
+    std::max_align_t    extension;
 };
 
 static const UText emptyText = UTEXT_INITIALIZER;
@@ -582,7 +584,7 @@ utext_setup(UText *ut, int32_t extraSpac
         // We need to heap-allocate storage for the new UText
         int32_t spaceRequired = sizeof(UText);
         if (extraSpace > 0) {
-            spaceRequired = sizeof(ExtendedUText) + extraSpace - sizeof(max_align_t);
+            spaceRequired = sizeof(ExtendedUText) + extraSpace - sizeof(std::max_align_t);
         }
         ut = (UText *)uprv_malloc(spaceRequired);
         if (ut == NULL) {