Make sure 'linkage.h' headers are installed. Add hack to bootstrap newer

versions of GCC. Filter out 'gnu99' from assembly flags. Use the 
'headers' target instead of 'pregen' to prepare for more NPTL 
integration. Fix broken MTD package configuration....someone believes in 
the Klingon release process apparently. Fix build issues with netplug 
and libpng. Fix source path for microcom as original site no longer 
exists.

package/libpng/remove-setjmp-error.patch

@@ -0,0 +1,17 @@
+diff -ur libpng-1.2.16/pngconf.h libpng-1.2.16-patched/pngconf.h
+--- libpng-1.2.16/pngconf.h	2007-01-31 07:22:33.000000000 -0600
++++ libpng-1.2.16-patched/pngconf.h	2008-02-27 17:40:23.707516659 -0600
+@@ -310,13 +310,6 @@
+ #      define PNG_SAVE_BSD_SOURCE
+ #      undef _BSD_SOURCE
+ #    endif
+-#    ifdef _SETJMP_H
+-     /* If you encounter a compiler error here, see the explanation
+-      * near the end of INSTALL.
+-      */
+-         __png.h__ already includes setjmp.h;
+-         __dont__ include it again.;
+-#    endif
+ #  endif /* __linux__ */
+ 
+    /* include setjmp.h for error handling */