Better error code when lacking __SIZEOF_INT128__

Fixes #6327

Reviewed-by: Andy Polyakov <appro@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6328)
diff --git a/crypto/ec/ecp_nistp224.c b/crypto/ec/ecp_nistp224.c
index 5b8da3f..364b7f2 100644
--- a/crypto/ec/ecp_nistp224.c
+++ b/crypto/ec/ecp_nistp224.c
@@ -45,7 +45,7 @@
 typedef __uint128_t uint128_t;  /* nonstandard; implemented by gcc on 64-bit
                                  * platforms */
 # else
-#  error "Need GCC 4.0 or later to define type uint128_t"
+#  error "Your compiler doesn't appear to support 128-bit integer types"
 # endif
 
 typedef uint8_t u8;
diff --git a/crypto/ec/ecp_nistp256.c b/crypto/ec/ecp_nistp256.c
index 5eee25c..19caa03 100644
--- a/crypto/ec/ecp_nistp256.c
+++ b/crypto/ec/ecp_nistp256.c
@@ -47,7 +47,7 @@
                                  * platforms */
 typedef __int128_t int128_t;
 # else
-#  error "Need GCC 4.0 or later to define type uint128_t"
+#  error "Your compiler doesn't appear to support 128-bit integer types"
 # endif
 
 typedef uint8_t u8;
diff --git a/crypto/ec/ecp_nistp521.c b/crypto/ec/ecp_nistp521.c
index 97846f8..3f68ae3 100644
--- a/crypto/ec/ecp_nistp521.c
+++ b/crypto/ec/ecp_nistp521.c
@@ -45,7 +45,7 @@
 typedef __uint128_t uint128_t;  /* nonstandard; implemented by gcc on 64-bit
                                  * platforms */
 # else
-#  error "Need GCC 4.0 or later to define type uint128_t"
+#  error "Your compiler doesn't appear to support 128-bit integer types"
 # endif
 
 typedef uint8_t u8;