Gábor Szeder authored Jan 17, 2019 and Junio C Hamano committed Jan 17, 2019

GCC 8 introduced the new -Wcast-function-type warning, which is
implied by -Wextra (which, in turn is enabled in our DEVELOPER flags).
When building Git with GCC 8 and this warning enabled on a non-glibc
platform [1], one is greeted with a screenful of compiler
warnings/errors:

  compat/obstack.c: In function '_obstack_begin':
  compat/obstack.c:162:17: error: cast between incompatible function types from 'void * (*)(long int)' to 'struct _obstack_chunk * (*)(void *, long int)' [-Werror=cast-function-type]
     h->chunkfun = (struct _obstack_chunk * (*)(void *, long)) chunkfun;
                   ^
  compat/obstack.c:163:16: error: cast between incompatible function types from 'void (*)(void *)' to 'void (*)(void *, struct _obstack_chunk *)' [-Werror=cast-function-type]
     h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun;
                  ^
  compat/obstack.c:116:8: error: cast between incompatible function types from 'struct _obstack_...