CVS commit by mueller: 

blacklist gcc 4.0.0. Its the first compiler we have to blacklist
because it miscompiles KDE.


  M +37 -0     acinclude.m4.in   2.510


--- kde-common/admin/acinclude.m4.in  #2.509:2.510
@@ -2909,4 +2909,39 @@
 ])
 
+
+AC_DEFUN([KDE_CHECK_FOR_BAD_COMPILER],
+[
+  AC_MSG_CHECKING([whether $CC is blacklisted])
+
+
+  AC_TRY_COMPILE([
+#ifdef __GNUC__
+#if __GNUC__ == 4 && __GNUC_MINOR__ == 0 && __GNUC_PATCHLEVEL__ == 0
+choke me
+#endif
+#endif
+], ,
+  kde_bad_compiler=no, 
+  kde_bad_compiler=yes
+)
+
+  AC_MSG_RESULT($kde_bad_compiler)
+
+if test "$kde_bad_compiler" = "yes"; then
+  AC_MSG_ERROR([
+
+This particular compiler version is blacklisted because it
+is known to miscompile KDE. Please use a newer version, or
+if that is not yet available, choose an older version. 
+
+Please do not report a bug or bother us reporting this
+configure error. We know about it, and we introduced
+it by intention to avoid untraceable bugs or crashes in KDE.
+
+])
+fi
+
+])
+
 dnl AC_VALIDIFY_CXXFLAGS checks for forbidden flags the user may have given
 AC_DEFUN([AC_VALIDIFY_CXXFLAGS],
@@ -3018,4 +3053,6 @@
   AC_PROG_CXX
 
+  KDE_CHECK_FOR_BAD_COMPILER
+
   if test "$GXX" = "yes" || test "$CXX" = "KCC"; then
     if test "$kde_use_debug_code" != "no"; then