Fix build.bat and support multiple compilers

Brovan.Graphics/brovvulk-icd/build.bat

@@ -4,6 +4,8 @@ setlocal EnableExtensions EnableDelayedExpansion
 set "HERE=%~dp0"
 set "REPO=%GITHUB_WORKSPACE%"
 
+if defined REPO if not exist "%REPO%" set "REPO="
+
 if not defined REPO (
     for /f "delims=" %%i in ('git -C "%HERE%" rev-parse --show-toplevel 2^>nul') do set "REPO=%%i"
 )
@@ -22,40 +24,95 @@ if not exist "%HERE%obj\generated\exports.def" (
     exit /b 1
 )
 
-if not exist "%HERE%bin" mkdir "%HERE%bin"
-if not exist "%HERE%obj\build" mkdir "%HERE%obj\build"
+if not exist "%HERE%bin" md "%HERE%bin" || exit /b 1
+if not exist "%HERE%obj\build" md "%HERE%obj\build" || exit /b 1
+
+set "COMPILER="
+set "MODE="
 
 where cl >nul 2>&1
-if errorlevel 1 call :init_msvc
-where cl >nul 2>&1
-if errorlevel 1 (
-    echo error: cl.exe not found. Run this from a Visual Studio developer environment on GitHub Actions Windows runners. 1>&2
-    exit /b 1
+if not errorlevel 1 (
+    for /f "delims=" %%C in ('where cl 2^>nul') do (
+        set "COMPILER=%%~fC"
+        set "MODE=msvc"
+        goto :have_compiler
+    )
+)
+
+where clang-cl >nul 2>&1
+if not errorlevel 1 (
+    if not defined VSCMD_VER call :init_msvc
+    if not errorlevel 1 (
+        for /f "delims=" %%C in ('where clang-cl 2^>nul') do (
+            set "COMPILER=%%~fC"
+            set "MODE=msvc"
+            goto :have_compiler
+        )
+    )
+)
+
+for %%T in (gcc clang cc) do (
+    if not defined COMPILER (
+        for /f "delims=" %%C in ('where %%T 2^>nul') do (
+            set "COMPILER=%%~fC"
+            set "MODE=gnu"
+            goto :have_compiler
+        )
+    )
+)
+
+call :init_msvc
+if not errorlevel 1 (
+    where cl >nul 2>&1
+    if not errorlevel 1 (
+        for /f "delims=" %%C in ('where cl 2^>nul') do (
+            set "COMPILER=%%~fC"
+            set "MODE=msvc"
+            goto :have_compiler
+        )
+    )
+
+    where clang-cl >nul 2>&1
+    if not errorlevel 1 (
+        for /f "delims=" %%C in ('where clang-cl 2^>nul') do (
+            set "COMPILER=%%~fC"
+            set "MODE=msvc"
+            goto :have_compiler
+        )
+    )
+)
+
+echo error: no supported compiler found. Install MSVC, clang-cl, gcc, or clang. 1>&2
+exit /b 1
+
+:have_compiler
+pushd "%HERE%" || exit /b 1
+
+if /i "%MODE%"=="msvc" (
+    "%COMPILER%" /nologo /O2 /MT /LD vulkan_shim.c /I. /I"..\vulkan-headers" /Fo"obj\build\" /Fe"bin\vulkan-1.dll" /link /DEF:"obj\generated\exports.def" /IMPLIB:"bin\vulkan-1.lib" kernel32.lib
+) else (
+    "%COMPILER%" -O2 -c "vulkan_shim.c" -I. -I"..\vulkan-headers" -o "obj\build\vulkan_shim.o"
+    if not errorlevel 1 (
+        "%COMPILER%" -shared -o "bin\vulkan-1.dll" "obj\build\vulkan_shim.o" "obj\generated\exports.def" -Wl,--out-implib,"bin\vulkan-1.lib"
+    )
 )
 
-pushd "%HERE%"
-cl /nologo /O2 /MT /LD vulkan_shim.c /I. /I..\vulkan-headers /Foobj\build\ /Febin\vulkan-1.dll /link /DEF:obj\generated\exports.def /IMPLIB:bin\vulkan-1.lib kernel32.lib
 if errorlevel 1 (
     popd
     exit /b 1
 )
+
 popd
 
 echo Deploying vulkan-1.dll:
-call :deploy "%REPO%\VirtualFS"
 
-if exist "%REPO%\Brovan\bin" (
-    for /r "%REPO%\Brovan\bin" %%E in (Brovan.exe) do call :deploy "%%~dpE\VirtualFS"
-)
-
-if exist "%REPO%\Brovan.Graphics" (
-    for /r "%REPO%\Brovan.Graphics" %%E in (Brovan.exe) do call :deploy "%%~dpE\VirtualFS"
-)
+for /f "delims=" %%E in ('dir /s /b /a-d "%REPO%\Brovan\bin\Brovan.exe" 2^>nul') do call :deploy "%%~dpEVirtualFS"
 
 exit /b 0
 
 :init_msvc
 set "VSDEVCMD="
+
 for %%P in (
     "%ProgramFiles(x86)%\Microsoft Visual Studio\2022\Enterprise\Common7\Tools\VsDevCmd.bat"
     "%ProgramFiles(x86)%\Microsoft Visual Studio\2022\Professional\Common7\Tools\VsDevCmd.bat"
@@ -66,14 +123,14 @@ for %%P in (
     "%ProgramFiles(x86)%\Microsoft Visual Studio\2019\Community\Common7\Tools\VsDevCmd.bat"
     "%ProgramFiles(x86)%\Microsoft Visual Studio\2019\BuildTools\Common7\Tools\VsDevCmd.bat"
 ) do (
-    if exist %%~P (
+    if exist "%%~P" (
         set "VSDEVCMD=%%~P"
         goto :have_vsdevcmd
     )
 )
 
-for /f "usebackq delims=" %%P in (`where vswhere.exe 2^>nul`) do (
-    for /f "usebackq delims=" %%Q in (`"%%P" -latest -products * -requires Microsoft.Component.MSBuild -find Common7\Tools\VsDevCmd.bat 2^>nul`) do (
+for /f "delims=" %%P in ('where vswhere.exe 2^>nul') do (
+    for /f "delims=" %%Q in ('"%%P" -latest -products * -requires Microsoft.Component.MSBuild -find Common7\Tools\VsDevCmd.bat 2^>nul') do (
         if exist "%%Q" (
             set "VSDEVCMD=%%Q"
             goto :have_vsdevcmd
@@ -85,11 +142,12 @@ exit /b 1
 
 :have_vsdevcmd
 call "%VSDEVCMD%" -arch=amd64 -host_arch=amd64 >nul
-exit /b 0
+exit /b %errorlevel%
 
 :deploy
 set "VFS=%~1\C\Windows\System32"
-if not exist "%VFS%" mkdir "%VFS%"
+if not exist "%VFS%" md "%VFS%" || exit /b 1
 copy /Y "%HERE%bin\vulkan-1.dll" "%VFS%\vulkan-1.dll" >nul
+if errorlevel 1 exit /b 1
 echo   deployed -^> %VFS%\vulkan-1.dll
 exit /b 0