Add mingw32-w64/wine CI build

.cirrus.yml

@@ -196,3 +196,24 @@ task:
     - rm /etc/ld.so.cache
     - ./ci/cirrus.sh
   << : *CAT_LOGS
+
+task:
+  name: "x86_64 (mingw32-w64): Windows (Debian stable, Wine)"
+  container:
+    dockerfile: ci/linux-debian.Dockerfile
+    cpu: 1
+    memory: 1G
+  env:
+    WINE_CMD: wine64-stable
+    HOST: x86_64-w64-mingw32
+    BUILD:
+    WITH_VALGRIND: no
+    ECDH: yes
+    RECOVERY: yes
+    EXPERIMENTAL: yes
+    SCHNORRSIG: yes
+    CTIMETEST: no
+  << : *MERGE_BASE
+  test_script:
+    - ./ci/cirrus.sh
+  << : *CAT_LOGS

ci/cirrus.sh

@@ -25,7 +25,7 @@ valgrind --version || true
 make
 
 # Print information about binaries so that we can see that the architecture is correct
-file *tests || true
+file *tests* || true
 file bench_* || true
 file .libs/* || true
 
@@ -47,6 +47,12 @@ then
     $QEMU_CMD ./exhaustive_tests
 fi
 
+if [ -n "$WINE_CMD" ]
+then
+    $WINE_CMD ./tests 16
+    $WINE_CMD ./exhaustive_tests
+fi
+
 if [ "$BENCH" = "yes" ]
 then
     # Using the local `libtool` because on macOS the system's libtool has nothing to do with GNU libtool
@@ -59,6 +65,10 @@ then
     then
         EXEC="$EXEC valgrind --error-exitcode=42"
     fi
+    if [ -n "$WINE_CMD" ]
+    then
+        EXEC="$WINE_CMD"
+    fi
     # This limits the iterations in the benchmarks below to ITER iterations.
     export SECP256K1_BENCH_ITERS="$ITERS"
     {

ci/linux-debian.Dockerfile

@@ -10,4 +10,8 @@ RUN apt-get install --no-install-recommends --no-upgrade -y \
         make automake libtool pkg-config dpkg-dev valgrind qemu-user \
         gcc clang libc6-dbg \
         gcc-i686-linux-gnu libc6-dev-i386-cross libc6-dbg:i386 \
-        gcc-s390x-linux-gnu libc6-dev-s390x-cross libc6-dbg:s390x
+        gcc-s390x-linux-gnu libc6-dev-s390x-cross libc6-dbg:s390x \
+        wine gcc-mingw-w64-x86-64
+
+# Run a dummy command in wine to make it set up configuration
+RUN wine64-stable xcopy || true

src/testrand_impl.h

@@ -127,7 +127,7 @@ static void secp256k1_testrand_init(const char* hexseed) {
             pos++;
         }
     } else {
-        FILE *frand = fopen("/dev/urandom", "r");
+        FILE *frand = fopen("/dev/urandom", "rb");
         if ((frand == NULL) || fread(&seed16, 1, sizeof(seed16), frand) != sizeof(seed16)) {
             uint64_t t = time(NULL) * (uint64_t)1337;
             fprintf(stderr, "WARNING: could not read 16 bytes from /dev/urandom; falling back to insecure PRNG\n");