Small debugging hack program to probe the PXE stack entry
conditions.  This is mostly useful when developing a PXE stack,
but might possibly be handy for finding workarounds for a stack,
too.

vesainfo.c32 is turning into an invaluable debugging tool.  Put it in
"modules" instead of "samples", to encourage distros to package it.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

"make clean" must NOT remove stuff that "make installer" should not
rebuild.  This is a somewhat unfortunate choice of naming, but that's
the way it is.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Cleanup and centralize the Makefile system even more.
Fix a gcc 4.3 incompatibility in memdisk (definition of strlen).

Compile with -std=gnu99, this allows us to define initializers inside
for() loops, which makes certain kinds of ugly macros easier to write.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Begin the process of centralizing configurables.

Improve "make install" and "make netinstall"; add "make
extbootinstall".

Move source files out of the root directory; the root is a mess and
has become virtually unmaintainable.  The Syslinux core now lives in
core/; the Linux and generic utilities has moved into utils/, and
copybs.com has moved into dos/; it had to go somewhere, and it seemed
as good a place as any.

Remove reference to readpit.c32, an experimental module never intended
for release.

Use $(CC) in gcc_ok macro, not plain gcc.  This seems to work, iff the
gcc_ok macro is declared with =, not :=