2 files changed, 21 insertions, 9 deletions
diff --git a/config_os.h b/config_os.h
index c6cd0eae..107e4452 100644
--- a/config_os.h
+++ b/config_os.h
@@ -27,9 +27,10 @@
 // It is OK to remove the hard stop below, but you are on your own.
 // After building the library be sure to run self tests described
 // https://www.cryptopp.com/wiki/Release_Process#Self_Tests
-// Some relevant bug reports can be found at:
-// * Clang: http://github.com/weidai11/cryptopp/issues/147
-#if (defined(_MSC_VER) && defined(__clang__) && !(defined( __clang_analyzer__)) && !defined(__INTEL_LLVM_COMPILER))
+// The problems with Clang pretending to be other compilers is
+// discussed at http://github.com/weidai11/cryptopp/issues/147.
+#if (defined(_MSC_VER) && defined(__clang__) && \
+   !(defined( __clang_analyzer__)) && !defined(__INTEL_LLVM_COMPILER))
 # error: "Unsupported configuration"
 #endif
 
diff --git a/config_ver.h b/config_ver.h
index 524b08fc..178eafea 100644
--- a/config_ver.h
+++ b/config_ver.h
@@ -58,12 +58,8 @@
 # define CRYPTOPP_GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
 #endif
 
-#if defined(__xlc__) || defined(__xlC__)
-# define CRYPTOPP_XLC_VERSION ((__xlC__ / 256) * 10000 + (__xlC__ % 256) * 100)
-#endif
-
-// Apple and LLVM's Clang. Apple Clang version 7.0 roughly equals LLVM Clang version 3.7
-// Also see https://gist.github.com/yamaya/2924292
+// Apple and LLVM Clang versions. Apple Clang version 7.0 roughly equals
+// LLVM Clang version 3.7. Also see https://gist.github.com/yamaya/2924292
 #if defined(__clang__) && defined(__apple_build_version__)
 # undef CRYPTOPP_GCC_VERSION
 # define CRYPTOPP_APPLE_CLANG_VERSION (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__)
@@ -72,7 +68,22 @@
 # define CRYPTOPP_LLVM_CLANG_VERSION  (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__)
 #endif
 
+// Clang pretends to be other compilers. The compiler gets into
+// code paths that it cannot compile. Unset Clang to save the grief.
+// Also see http://github.com/weidai11/cryptopp/issues/147.
+
+#if defined(__xlc__) || defined(__xlC__)
+# undef CRYPTOPP_LLVM_CLANG_VERSION
+# define CRYPTOPP_XLC_VERSION ((__xlC__ / 256) * 10000 + (__xlC__ % 256) * 100)
+#endif
+
+#ifdef __INTEL_COMPILER
+# undef CRYPTOPP_LLVM_CLANG_VERSION
+# define CRYPTOPP_INTEL_VERSION (__INTEL_COMPILER)
+#endif
+
 #ifdef _MSC_VER
+# undef CRYPTOPP_LLVM_CLANG_VERSION
 # define CRYPTOPP_MSC_VERSION (_MSC_VER)
 #endif