ci(msvc): compile launcher with MAGOS_TEST_BUILD for tests (+ Makefile Rust prereqs)

MSVC CI linked launcher.obj (compiled without the MAGOS_TEST_BUILD
guard, so it retained main()) into test_steam_env.exe and
test_injection.exe, which each define their own main -> LNK2005 /
LNK1169. Compile a guarded launcher_test.obj and link that into the
test exes instead; the production magos_launcher.exe stays unguarded.
Also move /SUBSYSTEM:WINDOWS off the cl compile line (D9002) to the
link step for stub_target.exe (it defines WinMain, so WINDOWS is
correct). Mirrors the Makefile's tests/launcher.o rule.

Makefile: the $(RUST_LIB) rule had no source prereqs, so incremental
builds linked a stale staticlib when only Rust sources changed. Add
discovery/src/*.rs + Cargo manifests as prereqs. (GNU make's ** is not
recursive and expands to nothing here, so src/*.rs is listed explicitly.)

Author: ModifAmorphic

.github/workflows/msvc-build.yml

@@ -68,19 +68,23 @@ jobs:
           set REL=target\x86_64-pc-windows-msvc\release
           :: Test runner object.
           cl /nologo /O2 /c tests\test_runner.c
-          :: Launcher object (for test linking).
-          cl /nologo /O2 /I launcher\src /c launcher\src\launcher.c
-          :: Stub target — minimal GUI exe.
-          cl /nologo /O2 /SUBSYSTEM:WINDOWS /Fe:tests\stub_target.exe tests\stub_target.c
+          :: Launcher object for test linking — compiled with MAGOS_TEST_BUILD so
+          :: launcher.c's main() is excluded (each test exe provides its own main).
+          :: Mirrors the Makefile's tests/launcher.o rule. The production
+          :: magos_launcher.exe (built above) is compiled WITHOUT the guard.
+          cl /nologo /O2 /I launcher\src /DMAGOS_TEST_BUILD /c launcher\src\launcher.c /Fo:launcher_test.obj
+          :: Stub target — minimal GUI exe (/SUBSYSTEM:WINDOWS is a linker flag,
+          :: so it goes after /link, not on the cl compile line).
+          cl /nologo /O2 /Fe:tests\stub_target.exe tests\stub_target.c /link /SUBSYSTEM:WINDOWS
           :: Stub shell — minimal DLL.
           cl /nologo /O2 /c tests\stub_shell.c
           link /nologo /DLL /OUT:tests\stub_shell.dll stub_shell.obj kernel32.lib
-          :: test_steam_env.exe
+          :: test_steam_env.exe — links the guarded launcher_test.obj (no main).
           cl /nologo /O2 /I launcher\src /Fe:tests\test_steam_env.exe ^
-             tests\test_steam_env.c test_runner.obj launcher.obj kernel32.lib
-          :: test_injection.exe
+             tests\test_steam_env.c test_runner.obj launcher_test.obj kernel32.lib
+          :: test_injection.exe — links the guarded launcher_test.obj (no main).
           cl /nologo /O2 /I launcher\src /Fe:tests\test_injection.exe ^
-             tests\test_injection.c test_runner.obj launcher.obj kernel32.lib
+             tests\test_injection.c test_runner.obj launcher_test.obj kernel32.lib
 
       - name: Run C unit tests (native)
         shell: cmd

Makefile

@@ -20,6 +20,10 @@ WINE      ?= wine
 
 REL_DIR   := target/$(TARGET)/$(PROFILE)
 RUST_LIB  := $(REL_DIR)/libmagos_discovery.a
+# Rust sources the staticlib depends on. GNU make's `**` is not recursive (it
+# expands to nothing here), so list src/*.rs explicitly. discovery/tests/*.rs
+# are separate integration-test binaries, not compiled into the staticlib.
+RUST_SRCS := $(wildcard discovery/src/*.rs)
 DLL       := magos_shell.dll
 LAUNCHER  := magos_launcher.exe
 
@@ -54,7 +58,7 @@ TEST_EXES := tests/test_steam_env.exe tests/test_injection.exe
 all: build
 
 rust-staticlib: $(RUST_LIB)
-$(RUST_LIB):
+$(RUST_LIB): $(RUST_SRCS) discovery/Cargo.toml Cargo.toml Cargo.lock
 	$(CARGO) build --$(PROFILE) -p magos-discovery --target $(TARGET)
 
 build: dll launcher