diff --git a/include/bitcoin/system/define.hpp b/include/bitcoin/system/define.hpp
index a41beced11..c47c3acf5a 100644
--- a/include/bitcoin/system/define.hpp
+++ b/include/bitcoin/system/define.hpp
@@ -79,16 +79,4 @@ namespace bc = libbitcoin;
     namespace libbitcoin { constexpr auto with_arm = false; };
 #endif
 
-/// Workarounds for C++ noncompliance.
-/// ---------------------------------------------------------------------------
-
-/// C++17 (partial), see HAVE_EXECUTION.
-#if defined(HAVE_EXECUTION)
-    namespace libbitcoin { constexpr auto par_unseq = std::execution::par_unseq; }
-    namespace libbitcoin { constexpr auto seq = std::execution::seq; }
-#else
-    namespace libbitcoin { constexpr auto par_unseq = false; }
-    namespace libbitcoin { constexpr auto seq = false; }
-#endif
-
 #endif
diff --git a/include/bitcoin/system/impl/hash/scrypt.ipp b/include/bitcoin/system/impl/hash/scrypt.ipp
index b18dd11de1..4b74537bb1 100644
--- a/include/bitcoin/system/impl/hash/scrypt.ipp
+++ b/include/bitcoin/system/impl/hash/scrypt.ipp
@@ -45,9 +45,9 @@ CONSTEVAL auto& CLASS::
 concurrency() NOEXCEPT
 {
     if constexpr (Concurrent)
-        return bc::par_unseq;
+        return std::execution::par;
     else
-        return bc::seq;
+        return std::execution::seq;
 }
 
 // protected
@@ -499,7 +499,7 @@ CLASS::hash(data_array<Size>& out, const data_slice& password,
     //    B[i] = scryptROMix (r, B[i], N)
     // end for
     std::atomic_bool success{ true };
-    std_for_each(concurrency(), prblocks.begin(), prblocks.end(),
+    std::for_each(concurrency(), prblocks.begin(), prblocks.end(),
         [&](rblock_t& rblock) NOEXCEPT
         {
             success = success && romix(rblock);
diff --git a/include/bitcoin/system/preprocessor.hpp b/include/bitcoin/system/preprocessor.hpp
index ccade62d24..bd0b1f6202 100644
--- a/include/bitcoin/system/preprocessor.hpp
+++ b/include/bitcoin/system/preprocessor.hpp
@@ -214,18 +214,9 @@
 /// C++17 (partial)
 #if defined(HAVE_EXECUTION)
     #include <execution>
-    #define std_any_of(p, b, e, l) std::any_of((p), (b), (e), (l))
-    #define std_all_of(p, b, e, l) std::all_of((p), (b), (e), (l))
-    #define std_for_each(p, b, e, l) std::for_each((p), (b), (e), (l))
-    #define std_reduce(p, b, e, i, l) std::reduce((p), (b), (e), (i), (l))
-    #define std_transform(p, b, e, t, l) std::transform((p), (b), (e), (t), (l))
 #else
+    #define POOLSTL_STD_SUPPLEMENT
     #include <bitcoin/system/execution.hpp>
-    #define std_any_of(p, b, e, l) std::any_of((b), (e), (l))
-    #define std_all_of(p, b, e, l) std::all_of((b), (e), (l))
-    #define std_for_each(p, b, e, l) std::for_each((b), (e), (l))
-    #define std_reduce(p, b, e, i, l) std::reduce((b), (e), (i), (l))
-    #define std_transform(p, b, e, t, l) std::transform((b), (e), (t), (l))
 #endif
 
 /// C++20 (partial)
diff --git a/test/hacks.cpp b/test/hacks.cpp
index 4c521e17d6..fb940d1ad2 100644
--- a/test/hacks.cpp
+++ b/test/hacks.cpp
@@ -19,7 +19,7 @@
 #include "test.hpp"
 #include <utility>
 
-#if defined(DISABLED) && defined(HAVE_EXECUTION)
+#if defined(DISABLED)
 
 BOOST_AUTO_TEST_SUITE(skip_parser_tests)