build: Stop checking for malloc() and memset() We do not provide alternatives for when memset() is missing, or when malloc() is not GNU-style malloc(), causing redirection to (undefined) rpl_malloc(). We do not rely on GNU-style malloc() at all, so there is no point in checking for it. [guillem@hadrons.org: - Slightly reword commit message. ] Signed-off-by: Guillem Jover <guillem@hadrons.org>