I found the cause for the memory-eating:
it's the optimization-flag.
I'm not an automake-guru, so it takes me a while to fin out how to switch it off only for headerfixup-plugin.
But at least it's quite easy.
Here is a patch for "Makefile.am" of headerfixup-plugin.
After applying it you have to run "./bootstrap" to regenerate "Makefile.in" what is used by "./configure".
--- /usr/src/c/codeblocks/codeblocks-1.0svn/src/plugins/contrib/headerfixup/Makefile.am 2008-07-09 07:20:42.000000000 +0200
+++ codeblocks-1.0svn/src/plugins/contrib/headerfixup/Makefile.am 2008-07-10 23:05:33.000000000 +0200
@@ -2,6 +2,8 @@
-I$(top_srcdir)/src/include \
-I$(top_srcdir)/src/include/wxscintilla/include
+CXXFLAGS = @CXXFLAGS@ -O0
+
libdir = $(pkgdatadir)/plugins
lib_LTLIBRARIES = libheaderfixup.la
This will add a "-O0" (the second one is a zero) to "CXXFLAGS" and overrides the "-O2" set before. The other flags will not be touched.