Patch VST3 SDK base to allow winelib compilation

meson.build

@@ -77,6 +77,8 @@ if with_vst3
   vst3 = subproject('vst3', version : '3.7.1')
   vst3_compiler_options = vst3.get_variable('compiler_options')
   vst3_include_dir = vst3.get_variable('include_dir')
+
+  # We'll create a dependency for the plugin SDK for our native VST3 plugin
   vst3_base_native = static_library(
     'base_native',
     vst3.get_variable('base_sources'),
@@ -106,6 +108,38 @@ if with_vst3
     link_with : vst3_sdk_native,
     include_directories : vst3_include_dir,
   )
+
+  # And another dependency for the host SDK for our Wine host applications
+  # We need to do some minor hacking to get this to compile with winegcc. Most
+  # notably some attributes are named differently, and the SDK uses 'Windows.h'
+  # instead of 'windows.h' like how the file is actually called.
+  # message(vst3_include_dir)
+  vst3_sdk_base_dir = vst3.get_variable('sdk_base_dir')
+  patch_result = run_command('tools/patch-vst3-sdk.sh', vst3_sdk_base_dir)
+  if patch_result.returncode() == 0
+    message(patch_result.stdout())
+  else
+    error('Error while trying to patch the VST3 SDK:\n' + patch_result.stderr())
+  endif
+
+  vst3_wine_compiler_options = [
+    # Removes some MSVC-isms for us
+    '-D__MINGW32__',
+    # We don't need all of this stuff from `Windows.h`, and it only causes more
+    # issues
+    '-DNOMINMAX',
+    '-DNOSERVICE',
+    '-DNOMCX',
+    '-DWIN32_LEAN_AND_MEAN',
+  ]
+  vst3_base_wine = static_library(
+    'base_wine',
+    vst3.get_variable('base_sources'),
+    cpp_args : vst3_compiler_options + vst3_wine_compiler_options + [ '-Wno-cpp'],
+    include_directories : vst3_include_dir,
+    override_options : ['warning_level=0'],
+    native : false,
+  )
 else
   message('VST3 support has been disabled')
 endif

subprojects/vst3.wrap

@@ -2,6 +2,6 @@
 url = https://github.com/robbert-vdh/vst3sdk.git
 # This is VST3 SDK v3.7.1_build_50 with the documentation and VSTGUI submodules
 # removed
-revision = d6d6ae0d33ada0c07a508b0e079d962464fa93cd
+revision = e2fbb41f28a4b311f2fc7d28e9b4330eec1802b6
 clone-recursive = true
 depth = 1

tools/patch-vst3-sdk.sh

@@ -0,0 +1,52 @@
+#!/usr/bin/env bash
+#
+# Patch the VST3 SDK and replace all MSVC-isms so it can be compiled with
+# winegcc. We do it this way instead of modifying the SDK directly so we don't
+# have to fork multiple repositories and keep them up to date.
+# If anyone knows a better way to get the SDK to compile with Win32 supports
+# under winegcc without having to modify it then please let me know, because I'd
+# rather not have to do this.
+#
+# Usage:
+# patch-vst3-sdk.sh <sdk_directory>
+
+set -euo pipefail
+
+sdk_directory=$1
+if [[ -z $sdk_directory ]]; then
+  echo "Usage:"
+  echo "patch-vst3-sdk.sh <sdk_directory>"
+  exit 1
+fi
+
+# Make sure all imports use the correct casing
+find "$sdk_directory" -type f \( -iname '*.h' -or -iname '*.cpp' \) -print0 |
+  xargs -0 sed -i 's/^#include <Windows.h>$/#include <windows.h>/'
+
+# Use the string manipulation functions from the C standard library
+sed -i 's/\bSMTG_OS_WINDOWS\b/0/g;s/\bSMTG_OS_LINUX\b/1/g' "$sdk_directory/base/source/fstring.cpp"
+sed -i 's/\bSMTG_OS_WINDOWS\b/0/g;s/\bSMTG_OS_LINUX\b/1/g' "$sdk_directory/pluginterfaces/base/fstrdefs.h"
+
+# We'll need some careful replacements in the Linux definitions in `fstring.cpp`
+# to use `wchar_t` instead of `char16_t`.
+sed -i "s/^using ConverterFacet = std::codecvt_utf8_utf16<char16_t>;$/#ifdef __WINE__\\
+    using ConverterFacet = std::codecvt_utf8_utf16<wchar_t>;\\
+#else\\
+    \0\\
+#endif/" "$sdk_directory/base/source/fstring.cpp"
+sed -i "s/^using Converter = std::wstring_convert<ConverterFacet, char16_t>;$/#ifdef __WINE__\\
+    using Converter = std::wstring_convert<ConverterFacet, wchar_t>;\\
+#else\\
+    \0\\
+#endif/" "$sdk_directory/base/source/fstring.cpp"
+
+# `Windows.h` expects `wchar_t`, and the above defines will cause us to use
+# `char16_t` for string literals. This replacement targets a very specific line,
+# so if the SDK gets updated, this fails, and we're getting a ton of `wchar_t`
+# related compile errors, that's why. The previous sed call will have replaced
+# `SMTG_OS_WINDOWS` with a 0 here.
+sed -i 's/^	#if 0$/	#if __WINE__/' "$sdk_directory/pluginterfaces/base/fstrdefs.h"
+
+# Meson requires this program to output something, or else it will error out
+# when trying to encode the empty output
+echo "Successfully patched '$sdk_directory' for winegcc compatibility"