document a problem with AIX native compiler and Apache 2+,

and describe how to avoid it

PR:   30487

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@105038 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/README.platforms b/README.platforms
index 3524cd1ea7b5c5da988a59e44e8795eef42766db..5307c104e1177493428da02f4f0a699372cedba0 100644 (file)
--- a/README.platforms
+++ b/README.platforms
@@ -82,5 +82,17 @@
      cc -c +z cpprt0_stub.s
        - OR -
      gcc -c -fPIC cpprt0_stub.s
+================
+  AIX, using the vendor C compiler with optimization:
+    There is an issue with compiling server/core.c with optimization enabled
+    which has been seen with C for AIX 5.0.2.3 and above.  (5.0.2.0, 5.0.2.1,
+    and 5.0.2.2 have an additional problem with Apache 2.0.x, so either upgrade 
+    the compiler or don't use optimization in order to avoid it.)
+
+    cc_r works fine with -O2 but xlc_r does not.  In order to use xlc_r with
+    -O2, apply the patch at 
+
+    http://www.apache.org/dist/httpd/patches/apply_to_2.0.49/aix_xlc_optimization.patch
 
+    (That patch works with many recent levels of Apache 2+.)