docker: fix dockerFile for secp256k1 building

[rjl493456442]

Fix #1352

[hadv]

@rjl493456442 this fix is for bitwalker/alpine-elixir-phoenix:latest, not for 1.7.1, right? because if I use 1.7.1 then still can build docker image without error

[rjl493456442]

@hadv It seems. I'll try to build with the current dockerfile. If it works I'll close it.

Thank you for reminding.

[rjl493456442]

I run the current dockerfile, still has such error:

make[1]: Leaving directory '/opt/app/deps/libsecp256k1/c_src/secp256k1'
cc -I/usr/lib/erlang/erts-10.0.3/include -I c_src/secp256k1 -I c_src/secp256k1/src -I c_src/secp256k1/include -I../libsecp256k1/src -fPIC -shared -o priv/libsecp256k1_nif.so c_src/libsecp256k1_nif.c c_src/secp256k1/.libs/libsecp256k1.a -lgmp
c_src/libsecp256k1_nif.c: In function 'ecdsa_sign':
c_src/libsecp256k1_nif.c:494:51: warning: passing argument 2 of 'secp256k1_ecdsa_signature_serialize_der' from incompatible pointer type [-Wincompatible-pointer-types]
  if (secp256k1_ecdsa_signature_serialize_der(ctx, &intermediatesig, &siglen, &signature) != 1) {
                                                   ^
In file included from c_src/libsecp256k1_nif.c:9:0:
c_src/secp256k1/src/secp256k1.c:261:5: note: expected 'unsigned char *' but argument is of type 'unsigned char (*)[74]'
 int secp256k1_ecdsa_signature_serialize_der(const secp256k1_context* ctx, unsigned char *output, size_t *outputlen, const secp256k1_ecdsa_signature* sig) {
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from c_src/secp256k1/src/secp256k1.c:9:0,
                 from c_src/libsecp256k1_nif.c:9:
c_src/libsecp256k1_nif.c:497:64: warning: passing argument 3 of 'secp256k1_ecdsa_signature_parse_der' from incompatible pointer type [-Wincompatible-pointer-types]
     CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &signature, &intermediatesig, siglen) == 1);
                                                                ^
c_src/secp256k1/src/util.h:40:39: note: in definition of macro 'EXPECT'
 #define EXPECT(x,c) __builtin_expect((x),(c))
                                       ^
c_src/libsecp256k1_nif.c:497:5: note: in expansion of macro 'CHECK'
     CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &signature, &intermediatesig, siglen) == 1);
     ^~~~~
In file included from c_src/libsecp256k1_nif.c:9:0:
c_src/secp256k1/src/secp256k1.c:224:5: note: expected 'const unsigned char *' but argument is of type 'unsigned char (*)[74]'
 int secp256k1_ecdsa_signature_parse_der(const secp256k1_context* ctx, secp256k1_ecdsa_signature* sig, const unsigned char *input, size_t inputlen) {
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/lib/gcc/x86_64-alpine-linux-musl/6.4.0/../../../../x86_64-alpine-linux-musl/bin/ld: cannot find -lgmp
collect2: error: ld returned 1 exit status
make: *** [Makefile:31: priv/libsecp256k1_nif.so] Error 1
==> libsecp256k1
[warning] Mix compiler :make_bindings was supposed to return :ok | :noop | {:ok | :noop | :error, [diagnostic]} but it returned :error

[hadv]

@rjl493456442 ah, sorry! Actually. I use your Dockerfile on puppeth's repo some days ago and can build with 1.7.1 I didnot check the Dockerfile on this repo

[acravenho]

LGTM 👍

[mattkanwisher]

Any reason this never got merged? We are experiencing similar issue

[rjl493456442]

@acravenho Can you merge this PR :) I think the fix really makes sense.

[acravenho]

@vbaranov can you please take a look and see if this can get merged? Thanks 👍

[vbaranov]

@rjl493456442 LGTM. I don't see the error mentioned in #1352 anymore.