Port better to AIX.

* configure.ac (CFLAGS): Append -O if the user did not specify CFLAGS,
we did not already infer an optimization option, and -O works.
AIX xlc needs -O, otherwise garbage collection doesn't work.
* src/lisp.h (ENUM_BF) [__IBMC__]: Make it 'unsigned int' here, too,
to pacify AIX xlc.

Fixes: debbugs:14258

2 files changed, 9 insertions, 3 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 99e2c3d9a84..9ae5c29ab72 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2013-04-26  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Port better to AIX (Bug#14258).
+        * lisp.h (ENUM_BF) [__IBMC__]: Make it 'unsigned int' here, too,
+        to pacify AIX xlc.
+
 2013-04-24  Kenichi Handa  <handa@gnu.org>
 
         * coding.c (decode_coding_iso_2022): When an invalid escape
diff --git a/src/lisp.h b/src/lisp.h
index bcb866b4cc4..e2c24eed352 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -231,9 +231,9 @@ enum enum_USE_LSB_TAG { USE_LSB_TAG = 0 };
 #define case_Lisp_Int case Lisp_Int0: case Lisp_Int1
 #define LISP_INT_TAG_P(x) (((x) & ~Lisp_Int1) == 0)
 
-/* Stolen from GDB.  The only known compiler that doesn't support
-   enums in bitfields is MSVC.  */
-#ifdef _MSC_VER
+/* Idea stolen from GDB.  MSVC doesn't support enums in bitfields,
+   and xlc complains vociferously about them.  */
+#if defined _MSC_VER || defined __IBMC__
 #define ENUM_BF(TYPE) unsigned int
 #else
 #define ENUM_BF(TYPE) enum TYPE