Normalize Wave EOF handling

Normalize root and include source buffers before lexing so EOF comments without a trailing newline no longer trip Wave.

Thanks-to: @Themperror for the repros

Author: AnastaZIuk

src/nbl/asset/utils/CHLSLCompiler.cpp

@@ -440,6 +440,12 @@ static void normalizeLegacyShaderStagePragmas(std::string& code)
     code = std::move(normalized);
 }
 
+static void ensureTrailingNewline(std::string& code)
+{
+    if (!code.empty() && code.back() != '\n' && code.back() != '\r')
+        code.push_back('\n');
+}
+
 static std::string preprocessShaderImpl(
     std::string&& code,
     IShader::E_SHADER_STAGE& stage,
@@ -464,6 +470,7 @@ static std::string preprocessShaderImpl(
         dependenciesOut = &localDependencies;
 
     normalizeLegacyShaderStagePragmas(code);
+    ensureTrailingNewline(code);
 
     // preprocess
     core::string resolvedString = nbl::wave::preprocess(code, preprocessOptions, bool(dependenciesOut),

src/nbl/asset/utils/waveContext.h

@@ -29,6 +29,8 @@ struct load_to_string final
             static void init_iterators(IterContextT& iter_ctx, PositionT const& act_pos, boost::wave::language_support language)
             {
                 iter_ctx.instring = iter_ctx.ctx.get_located_include_content();
+                if (!iter_ctx.instring.empty() && iter_ctx.instring.back() != '\n' && iter_ctx.instring.back() != '\r')
+                    iter_ctx.instring.push_back('\n');
 
                 using iterator_type = IterContextT::iterator_type;
                 iter_ctx.first = iterator_type(iter_ctx.instring.begin(),iter_ctx.instring.end(),PositionT(iter_ctx.filename),language);