Prepare for ICU's switch to char16_t

src/i18n.cc

Index: src/i18n.cc
diff --git a/src/i18n.cc b/src/i18n.cc
index d2245ef34a9a319a53b4cf4b4ea05ec095fef2d5..7c22871ff5e440f771659d44a0db013b34ec2105 100644
--- a/src/i18n.cc
+++ b/src/i18n.cc
@@ -30,8 +30,13 @@
 #include "unicode/ucol.h"
 #include "unicode/ucurr.h"
 #include "unicode/unum.h"
+#include "unicode/uvernum.h"
 #include "unicode/uversion.h"
 
+#if U_ICU_VERSION_MAJOR_NUM >= 59
+#include "unicode/char16ptr.h"
+#endif
+
 namespace v8 {
 namespace internal {
 
@@ -270,8 +275,13 @@ icu::DecimalFormat* CreateICUNumberFormat(
       }
 
       UErrorCode status_digits = U_ZERO_ERROR;
+#if U_ICU_VERSION_MAJOR_NUM >= 59
       uint32_t fraction_digits = ucurr_getDefaultFractionDigits(
-        currency.getTerminatedBuffer(), &status_digits);
+          icu::toUCharPtr(currency.getTerminatedBuffer()), &status_digits);
+#else
+      uint32_t fraction_digits = ucurr_getDefaultFractionDigits(
+          currency.getTerminatedBuffer(), &status_digits);
+#endif
       if (U_SUCCESS(status_digits)) {
         number_format->setMinimumFractionDigits(fraction_digits);
         number_format->setMaximumFractionDigits(fraction_digits);