Re: INSTALL: Fix names of host flags to match actual behaviour

[Andrei Borzenkov <arvidjaar@gmail.com>]

[Does Savannah offer GIT commits list?]

> -    3. CFLAGS= for C options for host.
> -    4. CPPFLAGS= for C preprocessor options for host.
> -    5. LDFLAGS= for linker options for host.
> +    3. HOST_CFLAGS= for C options for host.
> +    4. HOST_CPPFLAGS= for C preprocessor options for host.
> +    5. HOST_LDFLAGS= for linker options for host.

It is not that simple. 

a) we are using unchanged gnulib Makefile which knows nothing about
HOST_CFLAGS, which means, gnulib is compiled with different flags.

depbase=`echo xsize.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`;\
gcc -DHAVE_CONFIG_H -I. -I../..  -I../../intl -D_FILE_OFFSET_BITS=64   -MT xsize.o -MD -MP -MF $depbase.Tpo -c -o xsize.o xsize.c &&\
mv -f $depbase.Tpo $depbase.Po

So we actually *do* want CFLAGS to be used here, except that

b) automake always adds CFLAGS to compile command, this is quite deep
and I do not know how it can be changed. So any attempt to also set
CFLAGS will pollute target compile command that we do not want.

So far solutions I can think of are

1) patch gnulib Makefile to use HOST_CFLAGS
2) remove gnulib from SUBDIRS and explicitly call it with
CFLAGS=$(HOST_CFLAGS)
3a) make sure CFLAGS == HOST_CFLAGS in configure results
3b) ensure that CFLAGS is set to empty string in Makefile

We will probably need 3b anyway to avoid unintentional pollution of
target options. Otherwise I tend to consider 1 or 2 as this means "make
HOST_CFLAGS=xxx" will apply to both grub and gnulib.

Comments?