Apparently only MSVC can handle the ambiguity.

GPU/Common/FragmentShaderGenerator.cpp

@@ -31,7 +31,7 @@
 #include "GPU/ge_constants.h"
 #include "GPU/GPUState.h"
 
-#define WRITE(p, ...) p.W(__VA_ARGS__)
+#define WRITE(p, ...) p.F(__VA_ARGS__)
 
 bool GenerateFragmentShader(const FShaderID &id, char *buffer, const ShaderLanguageDesc &compat, uint64_t *uniformMask, std::string *errorString) {
 	*uniformMask = 0;

GPU/Common/ShaderWriter.cpp

@@ -59,7 +59,7 @@ const char *hlsl_preamble_vs =
 "\n";
 
 // Unsafe. But doesn't matter, we'll use big buffers for shader gen.
-void ShaderWriter::W(char *format, ...) {
+void ShaderWriter::F(const char *format, ...) {
 	va_list args;
 	va_start(args, format);
 	p_ += vsprintf(p_, format, args);
@@ -95,30 +95,30 @@ void ShaderWriter::Preamble(const char **gl_extensions, size_t num_gl_extensions
 		}
 		break;
 	default:  // OpenGL
-		W("#version %d%s\n", lang_.glslVersionNumber, lang_.gles && lang_.glslES30 ? " es" : "");
+		F("#version %d%s\n", lang_.glslVersionNumber, lang_.gles && lang_.glslES30 ? " es" : "");
 		switch (stage_) {
 		case ShaderStage::Fragment:
-			W("#define DISCARD discard\n");
+			C("#define DISCARD discard\n");
 			if (lang_.gles) {
-				W("precision lowp float;\n");
+				C("precision lowp float;\n");
 			}
 			break;
 		case ShaderStage::Vertex:
 			if (lang_.gles) {
-				W("precision highp float;\n");
+				C("precision highp float;\n");
 			}
 			break;
 		}
 		for (size_t i = 0; i < num_gl_extensions; i++) {
-			W("%s\n", gl_extensions[i]);
+			F("%s\n", gl_extensions[i]);
 		}
 		if (!lang_.gles) {
-			W("#define lowp\n");
-			W("#define mediump\n");
-			W("#define highp\n");
+			C("#define lowp\n");
+			C("#define mediump\n");
+			C("#define highp\n");
 		}
-		W("#define splat3(x) vec3(x)\n");
-		W("#define mul(x, y) ((x) * (y))\n");
+		C("#define splat3(x) vec3(x)\n");
+		C("#define mul(x, y) ((x) * (y))\n");
 		break;
 	}
 }

GPU/Common/ShaderWriter.h

@@ -15,20 +15,25 @@ public:
 		Preamble(gl_extensions, num_gl_extensions);
 	}
 
+	// I tried to call all three write functions "W", but only MSVC
+	// managed to disentangle the ambiguities, so had to give up on that.
+
 	// Assumes the input is zero-terminated.
+	// C : Copies a buffer directly to the stream.
 	template<size_t T>
-	void W(const char(&text)[T]) {
+	void C(const char(&text)[T]) {
 		memcpy(p_, text, T);
 		p_ += T;
 	}
+	// W: Writes a zero-terminated string to the stream.
 	void W(const char *text) {
 		size_t len = strlen(text);
 		memcpy(p_, text, len + 1);
 		p_ += len;
 	}
 
-	// Formats into the buffer.
-	void W(const char *format, ...);
+	// F: Formats into the buffer.
+	void F(const char *format, ...);
 
 	// void BeginMain();
 	// void EndMain();

GPU/Common/VertexShaderGenerator.cpp

@@ -32,7 +32,7 @@
 
 #undef WRITE
 
-#define WRITE(p, ...) p.W(__VA_ARGS__)
+#define WRITE(p, ...) p.F(__VA_ARGS__)
 
 static const char * const boneWeightAttrDecl[9] = {
 	"#ERROR#",

assets/lang

@@ -1 +1 @@
-Subproject commit fd6f5bc01afb419eacca538b425c01eb2a055393
+Subproject commit d5a2a51942377820764604d9bb424fa9a879c4bd