Fix incorrect description of USE_SLICING_BY_8_CRC32C.

And a typo in the description of USE_SSE42_CRC32C_WITH_RUNTIME_CHECK,
spotted by Daniel Gustafsson.

Author: hlinnaka

configure.in

@@ -1941,11 +1941,11 @@ if test x"$USE_SSE42_CRC32C" = x"1"; then
   AC_MSG_RESULT(SSE 4.2)
 else
   if test x"$USE_SSE42_CRC32C_WITH_RUNTIME_CHECK" = x"1"; then
-    AC_DEFINE(USE_SSE42_CRC32C_WITH_RUNTIME_CHECK, 1, [Define to 1 to use Intel SSSE 4.2 CRC instructions with a runtime check.])
+    AC_DEFINE(USE_SSE42_CRC32C_WITH_RUNTIME_CHECK, 1, [Define to 1 to use Intel SSE 4.2 CRC instructions with a runtime check.])
     PG_CRC32C_OBJS="pg_crc32c_sse42.o pg_crc32c_sb8.o pg_crc32c_choose.o"
     AC_MSG_RESULT(SSE 4.2 with runtime check)
   else
-    AC_DEFINE(USE_SLICING_BY_8_CRC32C, 1, [Define to 1 to use Intel SSE 4.2 CRC instructions with a runtime check.])
+    AC_DEFINE(USE_SLICING_BY_8_CRC32C, 1, [Define to 1 to use software CRC-32C implementation (slicing-by-8).])
     PG_CRC32C_OBJS="pg_crc32c_sb8.o"
     AC_MSG_RESULT(slicing-by-8)
   fi

src/include/pg_config.h.in

@@ -849,13 +849,13 @@
 /* Use replacement snprintf() functions. */
 #undef USE_REPL_SNPRINTF
 
-/* Define to 1 to use Intel SSE 4.2 CRC instructions with a runtime check. */
+/* Define to 1 to use software CRC-32C implementation (slicing-by-8). */
 #undef USE_SLICING_BY_8_CRC32C
 
 /* Define to 1 use Intel SSE 4.2 CRC instructions. */
 #undef USE_SSE42_CRC32C
 
-/* Define to 1 to use Intel SSSE 4.2 CRC instructions with a runtime check. */
+/* Define to 1 to use Intel SSE 4.2 CRC instructions with a runtime check. */
 #undef USE_SSE42_CRC32C_WITH_RUNTIME_CHECK
 
 /* Define to build with systemd support. (--with-systemd) */