windows-build: Get a C compiler to work again (#1105)

.github/workflows/build.yml

@@ -13,10 +13,9 @@ jobs:
       with:
         python-version: "3.8"  # last version supporting windows 7
     - run: pip install -r requirements.txt -r requirements-dev.txt
-    # FIXME: recompile launcher when this is fixed: https://github.com/egor-tensin/setup-mingw/issues/6
-#    - uses: egor-tensin/setup-mingw@v2
-#      with:
-#        platform: x64
+    - uses: egor-tensin/setup-clang@v1
+      with:
+        platform: x64
     # -u makes print show in real time
     - run: python -u scripts/build-exe-installer.py
     - uses: actions/upload-artifact@v2

README.md

@@ -259,17 +259,12 @@ Other people shouldn't need them.
 2. Make a pull request of your changelog edits. Review carefully:
     changing the changelog afterwards is difficult, as the text gets copied into the releases page.
 3. Merge the pull request and pull the merge commit to your local `master` branch.
-4. On a Windows computer (or VM), install Resource Hacker and change the version number in `launcher/Porcupine.exe`.
-    Hopefully I will eventually get a C compiler to work again,
-    so that this step can be skipped (see [#1086](https://github.com/Akuli/porcupine/pull/1086)).
-    ![resource-hacker.png](resource-hacker.png)
-    Push the new `.exe` file directly to master.
-5. Run `python3 scripts/release.py` from the `master` branch.
+4. Run `python3 scripts/release.py` from the `master` branch.
     The script pushes a tag named e.g. `v2022.07.29`,
     which triggers the parts of `.github/workflows/build.yml`
     that have `if: startsWith(github.ref, 'refs/tags/v')` in them.
     They build and deploy docs, copy the changelog to the releases page, and so on.
-6. Update `porcupine.wiki` if you added new features that are likely not obvious to users.
+5. Update `porcupine.wiki` if you added new features that are likely not obvious to users.
 
 If you want, you can also do a release from a branch named `bugfix-release` instead of `master`.
 This is useful if you fixed a bug that made Porcupine unusable for someone,

launcher/main.c

@@ -1,8 +1,8 @@
-#include <stdnoreturn.h>
 #include <stdlib.h>
 #include <string.h>
 #include <wchar.h>
 #include <windows.h>
+#include <stdnoreturn.h>
 
 static noreturn void fatal_error(const wchar_t *msg)
 {
@@ -13,8 +13,12 @@ static noreturn void fatal_error(const wchar_t *msg)
 
 typedef int(WINAPI *PyMainProc)(int argc, wchar_t **argv);
 
-int wmain(int argc, wchar_t **argv)
+int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PWSTR pCmdLine, int nCmdShow)
 {
+	// this is basically what cpython's PC/WinMain.c does
+	int argc = __argc;
+	wchar_t **argv = __wargv;
+
 	wchar_t *launcherpath = calloc(sizeof(launcherpath[0]), MAX_PATH);
 	if (!launcherpath)
 		fatal_error(L"allocating memory failed");

scripts/build-exe-installer.py

@@ -93,9 +93,8 @@
 print("Converting logo to .ico format")
 PIL.Image.open("porcupine/images/logo-200x200.gif").save("build/porcupine-logo.ico")
 
-# FIXME: Currently I can't get C compiler to work on github actions.
-#        I have committed a copy of the Porcupine.exe launcher here.
-#        Unfortunately the launcher contains an old version number that I can't update...
+# If you can't get a C compiler to work, you can install an older version of Porcupine and copy
+# its Porcupine.exe to launcher/Porcupine.exe
 if os.path.exists("build/launcher/Porcupine.exe"):
     print("Found launcher/Porcupine.exe, no C compiler needed")
 else:
@@ -108,14 +107,17 @@
     )
     subprocess.check_call(
         [
-            "gcc.exe",
+            "clang.exe",
             "-municode",
-            "-mwindows",
             "-o",
             "Porcupine.exe",
             "main.c",
             "icon.res",
             "metadata.res",
+            "-luser32",
+            # https://stackoverflow.com/a/37409970
+            # https://stackoverflow.com/q/64911334
+            "-Wl,/subsystem:windows",
         ],
         cwd="build/launcher",
     )