diff --git a/config.h b/config.h
index 50e34cf4..a05ba4e2 100644
--- a/config.h
+++ b/config.h
@@ -368,7 +368,7 @@ NAMESPACE_END
 # pragma GCC diagnostic ignored "-Wunused-function"
 #endif
 
-#if (defined(_MSC_VER) && _MSC_VER <= 1300) || defined(__MWERKS__) || defined(_STLPORT_VERSION)
+#if (defined(_MSC_VER) && _MSC_VER <= 1300) || defined(__MWERKS__) || (defined(_STLPORT_VERSION) && ((_STLPORT_VERSION < 0x450) || defined(_STLP_NO_UNCAUGHT_EXCEPT_SUPPORT)))
 #define CRYPTOPP_DISABLE_UNCAUGHT_EXCEPTION
 #endif
 
diff --git a/config.recommend b/config.recommend
index 8f11bfc0..5564ba0a 100644
--- a/config.recommend
+++ b/config.recommend
@@ -368,7 +368,7 @@ NAMESPACE_END
 # pragma GCC diagnostic ignored "-Wunused-function"
 #endif
 
-#if (defined(_MSC_VER) && _MSC_VER <= 1300) || defined(__MWERKS__) || defined(_STLPORT_VERSION)
+#if (defined(_MSC_VER) && _MSC_VER <= 1300) || defined(__MWERKS__) || (defined(_STLPORT_VERSION) && ((_STLPORT_VERSION < 0x450) || defined(_STLP_NO_UNCAUGHT_EXCEPT_SUPPORT)))
 #define CRYPTOPP_DISABLE_UNCAUGHT_EXCEPTION
 #endif
 
@@ -466,9 +466,10 @@ NAMESPACE_END
 #else
 #	define CRYPTOPP_CONSTANT(x) static const int x;
 #endif
-	
+
 // Linux provides X32, which is 32-bit integers, longs and pointers on x86_64 using the full x86_64 register set.
-// Detect via __ILP32__ (http://wiki.debian.org/X32Port). Both GCC and Clang provide the preprocessor macro.
+// Detect via __ILP32__ (http://wiki.debian.org/X32Port). However, __ILP32__ shows up in more places than
+// the System V ABI specs calls out, like on just about any 32-bit system with Clang.
 #if ((__ILP32__ >= 1) || (_ILP32 >= 1)) && defined(__x86_64__)
 	#define CRYPTOPP_BOOL_X32 1
 #else