gl_shader_gen: Always declare extensions after the version declaration

This addresses a bug on geometry shaders where code was being written
before all #extension declarations were done. Ref to #2523

src/video_core/renderer_opengl/gl_shader_cache.cpp

@@ -170,7 +170,8 @@ GLShader::ProgramResult CreateProgram(const Device& device, Maxwell::ShaderProgr
 CachedProgram SpecializeShader(const std::string& code, const GLShader::ShaderEntries& entries,
                                Maxwell::ShaderProgram program_type, BaseBindings base_bindings,
                                GLenum primitive_mode, bool hint_retrievable = false) {
-    std::string source = "#version 430 core\n";
+    std::string source = "#version 430 core\n"
+                         "#extension GL_ARB_separate_shader_objects : enable\n\n";
     source += fmt::format("#define EMULATION_UBO_BINDING {}\n", base_bindings.cbuf++);
 
     for (const auto& cbuf : entries.const_buffers) {

src/video_core/renderer_opengl/gl_shader_gen.cpp

@@ -19,8 +19,7 @@ static constexpr u32 PROGRAM_OFFSET{10};
 ProgramResult GenerateVertexShader(const Device& device, const ShaderSetup& setup) {
     const std::string id = fmt::format("{:016x}", setup.program.unique_identifier);
 
-    std::string out = "#extension GL_ARB_separate_shader_objects : enable\n\n";
-    out += "// Shader Unique Id: VS" + id + "\n\n";
+    std::string out = "// Shader Unique Id: VS" + id + "\n\n";
     out += GetCommonDeclarations();
 
     out += R"(
@@ -82,8 +81,7 @@ void main() {
 ProgramResult GenerateGeometryShader(const Device& device, const ShaderSetup& setup) {
     const std::string id = fmt::format("{:016x}", setup.program.unique_identifier);
 
-    std::string out = "#extension GL_ARB_separate_shader_objects : enable\n\n";
-    out += "// Shader Unique Id: GS" + id + "\n\n";
+    std::string out = "// Shader Unique Id: GS" + id + "\n\n";
     out += GetCommonDeclarations();
 
     out += R"(
@@ -113,8 +111,7 @@ void main() {
 ProgramResult GenerateFragmentShader(const Device& device, const ShaderSetup& setup) {
     const std::string id = fmt::format("{:016x}", setup.program.unique_identifier);
 
-    std::string out = "#extension GL_ARB_separate_shader_objects : enable\n\n";
-    out += "// Shader Unique Id: FS" + id + "\n\n";
+    std::string out = "// Shader Unique Id: FS" + id + "\n\n";
     out += GetCommonDeclarations();
 
     out += R"(