diff --git a/config/autoconf.mk.in b/config/autoconf.mk.in
index c6665094b6e..c8a5b417204 100644
--- a/config/autoconf.mk.in
+++ b/config/autoconf.mk.in
@@ -184,7 +184,6 @@ XLIBS		= @XLIBS@
 
 CYGWIN_WRAPPER	= @CYGWIN_WRAPPER@
 CYGDRIVE_MOUNT	= @CYGDRIVE_MOUNT@
-AIX_SHLIB_BIN	= @AIX_SHLIB_BIN@
 AR		= @AR@
 AR_FLAGS	= @AR_FLAGS@
 AR_EXTRACT	= @AR_EXTRACT@
diff --git a/configure.in b/configure.in
index 17a44bd5647..dce07b72a4f 100644
--- a/configure.in
+++ b/configure.in
@@ -802,19 +802,36 @@ dnl System overrides of the defaults for target
 dnl ========================================================
 case "$target" in
 *-aix*)
+    AC_DEFINE(AIX)
     if test ! "$GNU_CC"; then
-	    # DSO_LDOPTS='-ldl -bM:SRE -p1 -brtl -bso -bexpall -bnoentry'
-	    DSO_LDOPTS='-ldl -p1 -brtl -bso -bsymbolic -bnortllib'
-	    DSO_CFLAGS='-qflag=w:w'
-	    DSO_PIC_CFLAGS='-DPIC'
+        DSO_LDOPTS='-qmkshrobj=1 -G -bnoentry'
+        DSO_CFLAGS='-qflag=w:w'
+        DSO_PIC_CFLAGS=
+        LDFLAGS="$LDFLAGS -Wl,-brtl -blibpath:/usr/lib:/lib"
+        MKSHLIB='$(CXX) $(DSO_LDOPTS) -o $@'
+        MKCSHLIB='$(CC) $(DSO_LDOPTS) -o $@'
+        AC_LANG_SAVE
+        AC_LANG_CPLUSPLUS
+        AC_MSG_CHECKING([for VisualAge C++ compiler version >= 5.0.2.0])
+        AC_TRY_COMPILE([],
+            [#if (__IBMCPP__ < 520)
+             #error "Bad compiler"
+             #endif],
+            _BAD_COMPILER=,_BAD_COMPILER=1)
+        if test -n "$_BAD_COMPILER"; then
+            AC_MSG_RESULT([no])    
+            AC_MSG_ERROR([VisualAge C++ version 5.0.2.0 or higher is required to build.])
+        else
+            AC_MSG_RESULT([yes])    
+        fi
+        AC_LANG_RESTORE
     fi
     case "${target_os}" in
     aix4.1*)
         DLL_SUFFIX='_shr.a'
         ;;
     esac
-    MKSHLIB='$(AIX_SHLIB_BIN) $(DSO_LDOPTS) -o $@'
-    MKCSHLIB='$(AIX_SHLIB_BIN) $(DSO_LDOPTS) -o $@'
+    AC_CHECK_HEADERS(sys/inttypes.h)
     AC_DEFINE(NSCAP_DISABLE_DEBUG_PTR_TYPES)
     ;;
 
@@ -4635,42 +4652,6 @@ if test -n "$MOZ_STATIC_COMPONENTS" && test -n "$MOZ_META_COMPONENTS"; then
     AC_MSG_ERROR([Simultaneous use of meta-module-components & meta-components is not supported.])
 fi
 
-case "$target" in
-    *-*-aix*)
-	if test -z "${BUILD_STATIC_LIBS}" -o -n "${BUILD_SHARED_LIBS}"; then
-	    if test -f /usr/lpp/xlC/bin/makeC++SharedLib_r; then
-		AIX_SHLIB_BIN='/usr/lpp/xlC/bin/makeC++SharedLib_r'
-	    elif test -f /usr/vacpp/bin/makeC++SharedLib_r; then
-		AIX_SHLIB_BIN='/usr/vacpp/bin/makeC++SharedLib_r'
-	    elif test -f /usr/ibmcxx/bin/makeC++SharedLib_r; then
-		AIX_SHLIB_BIN='/usr/ibmcxx/bin/makeC++SharedLib_r'
-	    fi
-	    AC_PATH_PROG(AIX_SHLIB_BIN, makeC++SharedLib_r, :)
-	    if test ! -n "$AIX_SHLIB_BIN"; then
-		echo
-		echo "*** Unable to locate makeC++SharedLib_r, needed for creation of shared"
-		echo "*** libraries on AIX.  You will only be able to build static libraries."
-		echo
-		BUILD_STATIC_LIBS=1
-		BUILD_SHARED_LIBS=
-	    fi
-	fi
-	AC_SUBST(AIX_SHLIB_BIN)
-
-	dnl ========================================================
-	dnl Figure out if we are using a pre-5.0x version of the
-	dnl xlC compiler and if so, set flag
-	dnl ========================================================
-
-	if test ! "$GNU_CC" && test "$ac_cv_cpp_reinterpret_cast" = no ; then
-	   CXXFLAGS="$CXXFLAGS -DAIX_XLC_364"
-	   CFLAGS="$CFLAGS -DAIX_XLC_364"
-	fi
-
-	;;
-
-esac
-
 MOZ_COMPONENTLIB=
 MOZ_ARG_ENABLE_BOOL(componentlib,
 [  --enable-componentlib  Build a shared library containing all of the components],
diff --git a/js/src/jsotypes.h b/js/src/jsotypes.h
index ac71e2b51f5..1440963093a 100644
--- a/js/src/jsotypes.h
+++ b/js/src/jsotypes.h
@@ -89,7 +89,7 @@ typedef JSIntn intn;
  * So we don't define these four types here to avoid conflicts in case
  * the code also includes sys/types.h.
  */
-#ifdef AIX4_3
+#if defined(AIX) && defined(HAVE_SYS_INTTYPES_H)
 #include <sys/inttypes.h>
 #else
 typedef JSInt64 int64;
@@ -106,7 +106,7 @@ typedef long int32;
 typedef JSInt16 int16;
 typedef JSInt8 int8;
 #endif /* HPUX */
-#endif /* AIX4_3 */
+#endif /* AIX && HAVE_SYS_INTTYPES_H */
 
 #endif	/* XP_BEOS */
 
diff --git a/layout/generic/nsLineLayout.h b/layout/generic/nsLineLayout.h
index 1384fd8ff19..71467b7a9e4 100644
--- a/layout/generic/nsLineLayout.h
+++ b/layout/generic/nsLineLayout.h
@@ -398,9 +398,6 @@ protected:
   PerFrameData* mFrameFreeList;
   PRInt32 mInitialFramesFreed;
 
-#if defined(AIX_XLC_364)
-public:
-#endif
   struct PerSpanData {
     union {
       PerSpanData* mParent;
@@ -436,9 +433,6 @@ public:
       mLastFrame = pfd;
     }
   };
-#if defined(AIX_XLC_364)
-protected:
-#endif
   PerSpanData mSpanDataBuf[NS_LINELAYOUT_NUM_SPANS];
   PerSpanData* mSpanFreeList;
   PRInt32 mInitialSpansFreed;
diff --git a/layout/html/base/src/nsLineLayout.h b/layout/html/base/src/nsLineLayout.h
index 1384fd8ff19..71467b7a9e4 100644
--- a/layout/html/base/src/nsLineLayout.h
+++ b/layout/html/base/src/nsLineLayout.h
@@ -398,9 +398,6 @@ protected:
   PerFrameData* mFrameFreeList;
   PRInt32 mInitialFramesFreed;
 
-#if defined(AIX_XLC_364)
-public:
-#endif
   struct PerSpanData {
     union {
       PerSpanData* mParent;
@@ -436,9 +433,6 @@ public:
       mLastFrame = pfd;
     }
   };
-#if defined(AIX_XLC_364)
-protected:
-#endif
   PerSpanData mSpanDataBuf[NS_LINELAYOUT_NUM_SPANS];
   PerSpanData* mSpanFreeList;
   PRInt32 mInitialSpansFreed;