diff --git a/src/include/c.h b/src/include/c.h
index e84c77460c0250c655ecddb5de171c887ba99f8c..b719eb95e141e05c17ae2a4a1e897bbb6e3b732a 100644
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -53,20 +53,6 @@
 #include "pg_config.h"
 #include "pg_config_manual.h"	/* must be after pg_config.h */
 
-/*
- * Force disable inlining if PG_FORCE_DISABLE_INLINE is defined. This is used
- * to work around compiler bugs and might also be useful for investigatory
- * purposes.
- *
- * This is done early (in slightly the wrong section) for two reasons: a) we
- * don't want to include headers with different settings of this b)
- * functionality later in this file might want to rely on inline functions.
- */
-#ifdef PG_FORCE_DISABLE_INLINE
-#undef inline
-#define inline
-#endif
-
 /*
  * We always rely on the WIN32 macro being set by our build system,
  * but _WIN32 is the compiler pre-defined macro. So make sure we define
@@ -115,6 +101,19 @@
 #include "pg_config_os.h"
 #endif
 
+/*
+ * Force disable inlining if PG_FORCE_DISABLE_INLINE is defined. This is used
+ * to work around compiler bugs and might also be useful for investigatory
+ * purposes by defining the symbol in the platform's header..
+ *
+ * This is done early (in slightly the wrong section) as functionality later
+ * in this file might want to rely on inline functions.
+ */
+#ifdef PG_FORCE_DISABLE_INLINE
+#undef inline
+#define inline
+#endif
+
 /* Must be before gettext() games below */
 #include <locale.h>
 
diff --git a/src/include/port/aix.h b/src/include/port/aix.h
index dc4013e46e20111e94b629f900e4e0c65eba2c5b..5b1159c57857494e92f23a57168d76433531ca33 100644
--- a/src/include/port/aix.h
+++ b/src/include/port/aix.h
@@ -3,3 +3,12 @@
  */
 #define CLASS_CONFLICT
 #define DISABLE_XOPEN_NLS
+
+/*
+ * "IBM XL C/C++ for AIX, V12.1" miscompiles, for 32-bit, some inline
+ * expansions of ginCompareItemPointers() "long long" arithmetic.  To take
+ * advantage of inlining, build a 64-bit PostgreSQL.
+ */
+#if defined(__ILP32__) && defined(__IBMC__)
+#define PG_FORCE_DISABLE_INLINE
+#endif
diff --git a/src/template/aix b/src/template/aix
index f12023d7316e200c14c59c94e5365f1751c05fbe..b566ff129df6008b28d3b90470371e30e4f4adb4 100644
--- a/src/template/aix
+++ b/src/template/aix
@@ -12,14 +12,6 @@ if test "$GCC" != yes ; then
   esac
 fi
 
-# "IBM XL C/C++ for AIX, V12.1" miscompiles, for 32-bit, some inline
-# expansions of ginCompareItemPointers() "long long" arithmetic.  To
-# take advantage of inlining, build a 64-bit PostgreSQL.
-if test "$GCC" != yes -a $(getconf HARDWARE_BITMODE) == '32'; then
-  echo "$as_me: WARNING: disabling inlining on 32 bit aix due to a bug in xlc" 2>&1
-  CPPFLAGS="$CPPFLAGS -DPG_FORCE_DISABLE_INLINE"
-fi
-
 # Native memset() is faster, tested on:
 # 	AIX 5.1 and 5.2, XLC 6.0 (IBM's cc)
 # 	AIX 5.3 ML3, gcc 4.0.1