Merge bitcoin/bitcoin#28967: build: disable external-signer for Windows

308aec3e56 build: disable external-signer for Windows (fanquake)
35537318a1 ci: remove --enable-external-signer from win64 job (fanquake)

Pull request description:

  It's come to light that Boost ASIO (a Boost Process sub dep) has in some
  instances, been quietly  initialising our network stack on Windows (see
  PR https://github.com/bitcoin/bitcoin/pull/28486 and discussion in https://github.com/bitcoin/bitcoin/issues/28940).

  This has been shielding a bug in our own code, but the larger issue
  is that Boost Process/ASIO is running code before main, and doing things
  like setting up networking. This undermines our own assumptions about
  how our binary works, happens before we run any sanity checks,
  and before we call our own code to setup networking. Note that ASIO also
  calls WSAStartup with version `2.0`, whereas we call with `2.2`.

  It's also not clear why a feature like external signer would have a
  dependency that would be doing anything network/socket related,
  given it only exists to spawn a local process.

  See also the discussion in https://github.com/bitcoin/bitcoin/issues/24907. Note that the maintaince of Boost Process in general,
  has not really improved. For example, rather than fixing bugs like https://github.com/boostorg/process/issues/111,
  i.e, https://github.com/boostorg/process/pull/317, the maintainer chooses to just wrap exception causing overflows
  in try-catch blocks: 0c42a58eac. These changes get merged in large,
  unreviewed PRs, i.e https://github.com/boostorg/process/pull/319.

  This PR disables external-signer on Windows for now. If, in future, someone
  changes how Boost Process works, or replaces it entirely with some
  properly reviewed and maintained code, we could reenable this feature on
  Windows.

ACKs for top commit:
  hebasto:
    re-ACK 308aec3e56.
  TheCharlatan:
    ACK 308aec3e56

Tree-SHA512: 7405f7fc9833eeaacd6836c4e5b1c1a7845a40c1fdd55c1060152f8d8189e4777464fde650e11eb1539556a75dddf49667105987078b1457493ee772945da66e

build_msvc/bitcoin_config.h.in

@@ -41,9 +41,6 @@
 /* Define this symbol to enable ZMQ functions */
 #define ENABLE_ZMQ 1
 
-/* define if external signer support is enabled (requires Boost::Process) */
-#define ENABLE_EXTERNAL_SIGNER /**/
-
 /* Define to 1 if you have the declaration of `be16toh', and to 0 if you
    don't. */
 #define HAVE_DECL_BE16TOH 0

build_msvc/vcpkg.json

@@ -5,7 +5,6 @@
     "berkeleydb",
     "boost-date-time",
     "boost-multi-index",
-    "boost-process",
     "boost-signals2",
     "boost-test",
     "libevent",

ci/test/00_setup_env_win64.sh

@@ -16,4 +16,4 @@ export GOAL="deploy"
 # Prior to 11.0.0, the mingw-w64 headers were missing noreturn attributes, causing warnings when
 # cross-compiling for Windows. https://sourceforge.net/p/mingw-w64/bugs/306/
 # https://github.com/mingw-w64/mingw-w64/commit/1690994f515910a31b9fb7c7bd3a52d4ba987abe
-export BITCOIN_CONFIG="--enable-reduce-exports --enable-external-signer --disable-gui-tests CXXFLAGS=-Wno-return-type"
+export BITCOIN_CONFIG="--enable-reduce-exports --disable-gui-tests CXXFLAGS=-Wno-return-type"

configure.ac

@@ -1505,9 +1505,19 @@ if test "$use_external_signer" != "no"; then
   CXXFLAGS="$TEMP_CXXFLAGS"
   AC_MSG_RESULT([$have_boost_process])
   if test "$have_boost_process" = "yes"; then
-    use_external_signer="yes"
-    AC_DEFINE([ENABLE_EXTERNAL_SIGNER], [1], [Define if external signer support is enabled])
-    AC_DEFINE([BOOST_PROCESS_USE_STD_FS], [1], [Defined to avoid Boost::Process trying to use Boost Filesystem])
+    case $host in
+      dnl Boost Process for Windows uses Boost ASIO. Boost ASIO performs
+      dnl pre-main init of Windows networking libraries, which we do not
+      dnl want.
+      *mingw*)
+        use_external_signer="no"
+      ;;
+      *)
+        use_external_signer="yes"
+        AC_DEFINE([ENABLE_EXTERNAL_SIGNER], [1], [Define if external signer support is enabled])
+        AC_DEFINE([BOOST_PROCESS_USE_STD_FS], [1], [Defined to avoid Boost::Process trying to use Boost Filesystem])
+      ;;
+    esac
   else
     if test "$use_external_signer" = "yes"; then
       AC_MSG_ERROR([External signing is not supported for this Boost version])