Feature/file remove (#982)

* Work in progress to be able to invoke VS from within code.

* First pass at windows version of refactor of OSProcessSpawner

* Closer to getting VS path lookup working.

* Make OSString assignable/ctor able

* Work out program files directory directly, so don't have to expand %%.

* WIP: Improve handling of process spawning.

* Add support for splitting input by line.

* * Correctly locates visual studio install
* Added functionality to invoke vs via cmd

* Add option to execute the command line.

* Handle in ProcessUtil for windows -> WinHandle.

* Rename files slang-win-visual-studio-util.cpp/.h and slang-process-util.h

* First pass at unix/linux version of ProcessUtil.

* Fix reading Visual Studio path from the registry.

* Get compiling on linux with.

* Fix vcvarsall.bat name

* Use ProcessUtil to execute external code.

* Remove OSProcessSpawner.

* Remove includes for "os.h" where no longer needed.

* Fix tabbing issue in premake5.lua
Remove test code from slang-test-main.cpp

* Fix premake4.lua tabbing issue.

* Small fixes to slang-process-util.h
Init ExecuteResult on Win execute.

* Improve comments.

* Fix bug in StringUtil::calcLines - with oddly terminated source input being able to read past end.
Make slang-generate use StringUtil over it's own impl.

* Fix off by one bug in working out Visual Studio version.

* Fix bug in calculating Visual Studio Version

* Fix compilation on linux with string parameter being passed to messageFormat.

* Remove erroneous use of kOSError codes - use Result.

* First effort to generate standard compiler options.

* Initial efforts in compiling source code in test framework for VisualStudio.

* Testing compiling c code on VisualStudio on Windows.

* Fix warning on linux.

* Fix clang on linux warning (and therefore failing) returning a StringBuilder as String.

* Disable return-std-move on clang.

* CommandLine arguments are now tagged if they are escaped or not. That it is the clients responsibility to escape command lines that cannot be automatically escaped.

* Add checks on unix/linux that command line args are all unescaped.

* WIP getting runtime GCC to work.

* First pass compiler working on unix-like targets.

* Added File::remove function.

* Enable c-compile.c test on 'smoke'.

3 files changed, 25 insertions, 1 deletions

diff --git a/source/core/slang-io.cpp b/source/core/slang-io.cpp
index e52ea0704..a144c5892 100644
--- a/source/core/slang-io.cpp
+++ b/source/core/slang-io.cpp
@@ -31,6 +31,27 @@
 
 namespace Slang
 {
+
+    /* static */SlangResult File::remove(const String& fileName)
+    {
+#ifdef _WIN32
+        // https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-deletefilea
+        if (DeleteFileA(fileName.getBuffer()))
+        {
+            return SLANG_OK;
+        }
+        return SLANG_FAIL;
+#else
+        // https://linux.die.net/man/2/unlink
+
+        if (unlink(fileName.getBuffer()) == 0)
+        {
+            return SLANG_OK;
+        }
+        return SLANG_FAIL;
+#endif
+    }
+
 	bool File::exists(const String& fileName)
 	{
 #ifdef _WIN32
diff --git a/source/core/slang-io.h b/source/core/slang-io.h
index 64ec11c5a..4fa921662 100644
--- a/source/core/slang-io.h
+++ b/source/core/slang-io.h
@@ -15,6 +15,7 @@ namespace Slang
 		static Slang::String readAllText(const Slang::String& fileName);
 		static Slang::List<unsigned char> readAllBytes(const Slang::String& fileName);
 		static void writeAllText(const Slang::String& fileName, const Slang::String& text);
+        static SlangResult remove(const String& fileName);
 	};
 
 	class Path
diff --git a/tools/slang-test/slang-test-main.cpp b/tools/slang-test/slang-test-main.cpp
index 912d13b78..b93833f89 100644
--- a/tools/slang-test/slang-test-main.cpp
+++ b/tools/slang-test/slang-test-main.cpp
@@ -1103,6 +1103,9 @@ static TestResult runExecuteC(TestContext* context, TestInput& input)
     auto filePath = input.filePath;
     auto outputStem = input.outputStem;
 
+    String actualOutputPath = outputStem + ".actual";
+    File::remove(actualOutputPath);
+
     // Make the module name the same as the source file
     String directory = Path::getParentDirectory(input.outputStem);
     String moduleName = Path::getFileNameWithoutExt(filePath);
@@ -1162,7 +1165,6 @@ static TestResult runExecuteC(TestContext* context, TestInput& input)
 
         // Write the output, and compare to expected
         String actualOutput = getOutput(exeRes);
-        String actualOutputPath = outputStem + ".actual";
         Slang::File::writeAllText(actualOutputPath, actualOutput);
 
         // Read the expected