How to have two different makefile mapped to two different keys?

Question

I am using F5 to compile my programs
From my .vimrc

set makeprg=make\ -f\ ~/makefile\ %<
noremap <F5> :make<CR>

But I want to add one other way to compile my programs which compiles a bit slowly and use some other key say F4. I tried inserting another such statement below these lines but then F5 also compiles with the new makefile.

EDIT:
As asked in comments:

set makeprg=make\ -f\ ~/makefile\ %<
noremap <F5> :make<CR>
" slow compilation but more flags for more checks
set makeprg=make\ -f\ ~/makefile1\ %<
noremap <F4> :make<CR>

Answer 1

My understanding is that the makeprg setting is primarily used to change the actual make/build program and in your case the program isn't changing...it's always 'make'.

Since :make accepts arguments I suggest leaving 'makeprg' alone and passing your build command args to :make in the two mappings...

noremap <F4> :make -f ~/makefile1 %<<CR>
noremap <F5> :make -f ~/makefile %<<CR>

Regarding %<, which expands to the current filename minus its extension, in my comments I wavered on whether this would work or if you would need to use :exe and call expand() like so....

noremap <F4> :exe "make -f ~/makefile1 " . expand('%<')<CR>

Actually, you should be okay with the shorter versions.

BTW, %< is there for backwards compatibility with a very old version of vim, per :h :_%<. The synonym, :r, is now "preferred".