diff --git a/src/include/c.h b/src/include/c.h
index a48a57a..999f297 100644
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -864,6 +864,9 @@ typedef NameData *Name;
  * ----------------------------------------------------------------
  */
 
+#define INT64_FORMAT "%" INT64_MODIFIER "d"
+#define UINT64_FORMAT "%" INT64_MODIFIER "u"
+
 /* msb for char */
 #define HIGHBIT					(0x80)
 #define IS_HIGHBIT_SET(ch)		((unsigned char)(ch) & HIGHBIT)

diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index 2a40d61..c2e01fd 100644
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -650,8 +650,8 @@
 /* Define to 1 if your compiler understands __VA_ARGS__ in macros. */
 #undef HAVE__VA_ARGS
 
-/* Define to the appropriate snprintf format for 64-bit ints. */
-#undef INT64_FORMAT
+/* Define to the appropriate snprintf length modifier for 64-bit ints. */
+#undef INT64_MODIFIER
 
 /* Define to 1 if `locale_t' requires <xlocale.h>. */
 #undef LOCALE_T_IN_XLOCALE
@@ -741,9 +741,6 @@
 /* Define to 1 if your <sys/time.h> declares `struct tm'. */
 #undef TM_IN_SYS_TIME
 
-/* Define to the appropriate snprintf format for unsigned 64-bit ints. */
-#undef UINT64_FORMAT
-
 /* Define to 1 to build with assertion checks. (--enable-cassert) */
 #undef USE_ASSERT_CHECKING
 
diff --git a/src/include/pg_config.h.win32 b/src/include/pg_config.h.win32
index 1c9cd82..a238a72 100644
--- a/src/include/pg_config.h.win32
+++ b/src/include/pg_config.h.win32
@@ -529,8 +529,8 @@
 /* Define to 1 if your compiler understands __VA_ARGS__ in macros. */
 #define HAVE__VA_ARGS 1
 
-/* Define to the appropriate snprintf format for 64-bit ints, if any. */
-#define INT64_FORMAT "%lld"
+/* Define to the appropriate snprintf length modifier for 64-bit ints. */
+#undef INT64_MODIFIER
 
 /* Define to 1 if `locale_t' requires <xlocale.h>. */
 /* #undef LOCALE_T_IN_XLOCALE */
@@ -601,10 +601,6 @@
 /* Define to 1 if your <sys/time.h> declares `struct tm'. */
 /* #undef TM_IN_SYS_TIME */
 
-/* Define to the appropriate snprintf format for unsigned 64-bit ints, if any.
-   */
-#define UINT64_FORMAT "%llu"
-
 /* Define to 1 to build with assertion checks. (--enable-cassert) */
 /* #undef USE_ASSERT_CHECKING */
 
diff --git a/configure.in b/configure.in
index c938a5d..7750c30 100644
--- a/configure.in
+++ b/configure.in
@@ -1636,34 +1636,29 @@ fi
 # If we found "long int" is 64 bits, assume snprintf handles it.  If
 # we found we need to use "long long int", better check.  We cope with
 # snprintfs that use %lld, %qd, or %I64d as the format.  If none of these
-# work, fall back to our own snprintf emulation (which we know uses %lld).
+# works, fall back to our own snprintf emulation (which we know uses %lld).
 
 if test "$HAVE_LONG_LONG_INT_64" = yes ; then
   if test $pgac_need_repl_snprintf = no; then
-    PGAC_FUNC_SNPRINTF_LONG_LONG_INT_FORMAT
-    if test "$LONG_LONG_INT_FORMAT" = ""; then
+    PGAC_FUNC_SNPRINTF_LONG_LONG_INT_MODIFIER
+    if test "$LONG_LONG_INT_MODIFIER" = ""; then
       # Force usage of our own snprintf, since system snprintf is broken
       pgac_need_repl_snprintf=yes
-      LONG_LONG_INT_FORMAT='%lld'
+      LONG_LONG_INT_MODIFIER='ll'
     fi
   else
     # Here if we previously decided we needed to use our own snprintf
-    LONG_LONG_INT_FORMAT='%lld'
+    LONG_LONG_INT_MODIFIER='ll'
   fi
-  LONG_LONG_UINT_FORMAT=`echo "$LONG_LONG_INT_FORMAT" | sed 's/d$/u/'`
-  INT64_FORMAT="\"$LONG_LONG_INT_FORMAT\""
-  UINT64_FORMAT="\"$LONG_LONG_UINT_FORMAT\""
 else
   # Here if we are not using 'long long int' at all
-  INT64_FORMAT='"%ld"'
-  UINT64_FORMAT='"%lu"'
+  LONG_LONG_INT_MODIFIER='l'
 fi
 
-AC_DEFINE_UNQUOTED(INT64_FORMAT, $INT64_FORMAT,
-                   [Define to the appropriate snprintf format for 64-bit ints.])
+INT64_MODIFIER="\"$LONG_LONG_INT_MODIFIER\""
 
-AC_DEFINE_UNQUOTED(UINT64_FORMAT, $UINT64_FORMAT,
-                   [Define to the appropriate snprintf format for unsigned 64-bit ints.])
+AC_DEFINE_UNQUOTED(INT64_MODIFIER, $INT64_MODIFIER,
+                   [Define to the appropriate snprintf length modifier for 64-bit ints.])
 
 # Also force use of our snprintf if the system's doesn't support the %z flag.
 if test "$pgac_need_repl_snprintf" = no; then

diff --git a/config/c-library.m4 b/config/c-library.m4
index 8f45010..4821a61 100644
--- a/config/c-library.m4
+++ b/config/c-library.m4
@@ -221,22 +221,22 @@ HAVE_POSIX_SIGNALS=$pgac_cv_func_posix_signals
 AC_SUBST(HAVE_POSIX_SIGNALS)])# PGAC_FUNC_POSIX_SIGNALS
 
 
-# PGAC_FUNC_SNPRINTF_LONG_LONG_INT_FORMAT
+# PGAC_FUNC_SNPRINTF_LONG_LONG_INT_MODIFIER
 # ---------------------------------------
-# Determine which format snprintf uses for long long int.  We handle
-# %lld, %qd, %I64d.  The result is in shell variable
-# LONG_LONG_INT_FORMAT.
+# Determine which length modifier snprintf uses for long long int.  We
+# handle ll, q, and I64.  The result is in shell variable
+# LONG_LONG_INT_MODIFIER.
 #
 # MinGW uses '%I64d', though gcc throws an warning with -Wall,
 # while '%lld' doesn't generate a warning, but doesn't work.
 #
-AC_DEFUN([PGAC_FUNC_SNPRINTF_LONG_LONG_INT_FORMAT],
-[AC_MSG_CHECKING([snprintf format for long long int])
-AC_CACHE_VAL(pgac_cv_snprintf_long_long_int_format,
-[for pgac_format in '%lld' '%qd' '%I64d'; do
+AC_DEFUN([PGAC_FUNC_SNPRINTF_LONG_LONG_INT_MODIFIER],
+[AC_MSG_CHECKING([snprintf length modifier for long long int])
+AC_CACHE_VAL(pgac_cv_snprintf_long_long_int_modifier,
+[for pgac_modifier in 'll' 'q' 'I64'; do
 AC_TRY_RUN([#include <stdio.h>
 typedef long long int ac_int64;
-#define INT64_FORMAT "$pgac_format"
+#define INT64_FORMAT "%${pgac_modifier}d"
 
 ac_int64 a = 20000001;
 ac_int64 b = 40000005;
@@ -258,19 +258,19 @@ int does_int64_snprintf_work()
 main() {
   exit(! does_int64_snprintf_work());
 }],
-[pgac_cv_snprintf_long_long_int_format=$pgac_format; break],
+[pgac_cv_snprintf_long_long_int_modifier=$pgac_modifier; break],
 [],
-[pgac_cv_snprintf_long_long_int_format=cross; break])
+[pgac_cv_snprintf_long_long_int_modifier=cross; break])
 done])dnl AC_CACHE_VAL
 
-LONG_LONG_INT_FORMAT=''
+LONG_LONG_INT_MODIFIER=''
 
-case $pgac_cv_snprintf_long_long_int_format in
+case $pgac_cv_snprintf_long_long_int_modifier in
   cross) AC_MSG_RESULT([cannot test (not on host machine)]);;
-  ?*)    AC_MSG_RESULT([$pgac_cv_snprintf_long_long_int_format])
-         LONG_LONG_INT_FORMAT=$pgac_cv_snprintf_long_long_int_format;;
+  ?*)    AC_MSG_RESULT([$pgac_cv_snprintf_long_long_int_modifier])
+         LONG_LONG_INT_MODIFIER=$pgac_cv_snprintf_long_long_int_modifier;;
   *)     AC_MSG_RESULT(none);;
-esac])# PGAC_FUNC_SNPRINTF_LONG_LONG_INT_FORMAT
+esac])# PGAC_FUNC_SNPRINTF_LONG_LONG_INT_MODIFIER
 
 
 # PGAC_FUNC_SNPRINTF_ARG_CONTROL