diff --git a/include/__config b/include/__config
index aa8bc448..874bcc15 100644
--- a/include/__config
+++ b/include/__config
@@ -454,7 +454,6 @@ namespace std {
 #define _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
 #define _LIBCPP_HAS_NO_NULLPTR
 #define _LIBCPP_HAS_NO_UNICODE_CHARS
-#define _LIBCPP_HAS_NO_STRONG_ENUMS
 #define _LIBCPP_HAS_IS_BASE_OF
 
 #if defined(_AIX)
@@ -514,7 +513,7 @@ template <unsigned> struct __static_assert_check {};
 #define __has_feature(__x) 0
 #endif
 
-#if __has_feature(cxx_explicit_conversions)
+#if __has_feature(cxx_explicit_conversions) || defined(__IBMCPP__)
 #   define _LIBCPP_EXPLICIT explicit
 #else
 #   define _LIBCPP_EXPLICIT
diff --git a/include/support/ibm/support.h b/include/support/ibm/support.h
index 3effbaed..0abfa7f9 100644
--- a/include/support/ibm/support.h
+++ b/include/support/ibm/support.h
@@ -15,7 +15,7 @@ extern "builtin" int __popcnt4(unsigned int);
 extern "builtin" int __popcnt8(unsigned long long);
 extern "builtin" unsigned int __cnttz4(unsigned int);
 extern "builtin" unsigned int __cnttz8(unsigned long long);
-extern "builtin" unsigned int __cntlz4(unsigned long long);
+extern "builtin" unsigned int __cntlz4(unsigned int);
 extern "builtin" unsigned int __cntlz8(unsigned long long);
 
 // Builtin functions for counting population
diff --git a/src/locale.cpp b/src/locale.cpp
index a326323a..8e7fdb43 100644
--- a/src/locale.cpp
+++ b/src/locale.cpp
@@ -1036,7 +1036,7 @@ ctype<char>::classic_table()  _NOEXCEPT
 #elif defined(__EMSCRIPTEN__)
     return *__ctype_b_loc();
 #elif defined(_AIX)
-    return (const unsigned long *)__lc_ctype_ptr->obj->mask;
+    return (const unsigned int *)__lc_ctype_ptr->obj->mask;
 #else
     // Platform not supported: abort so the person doing the port knows what to
     // fix