shaders: Fix GCC and clang build issues.

src/video_core/engines/shader_bytecode.h

@@ -12,7 +12,7 @@ namespace Tegra {
 namespace Shader {
 
 struct Register {
-    constexpr Register() = default;
+    Register() = default;
 
     constexpr Register(u64 value) : value(value) {}
 
@@ -47,7 +47,7 @@ private:
 };
 
 union Attribute {
-    constexpr Attribute() = default;
+    Attribute() = default;
 
     constexpr Attribute(u64 value) : value(value) {}
 
@@ -118,7 +118,7 @@ union OpCode {
         std::string name;
     };
 
-    constexpr OpCode() = default;
+    OpCode() = default;
 
     constexpr OpCode(Id value) : value(static_cast<u64>(value)) {}
 

src/video_core/renderer_opengl/gl_resource_manager.h

@@ -131,7 +131,7 @@ public:
     }
 
     template <typename... T>
-    void Create(bool separable_program = false, T... shaders) {
+    void Create(bool separable_program, T... shaders) {
         if (handle != 0)
             return;
         handle = GLShader::LoadProgram(separable_program, shaders...);

src/video_core/renderer_opengl/gl_shader_decompiler.cpp

@@ -236,7 +236,7 @@ private:
 
         switch (OpCode::GetInfo(instr.opcode).type) {
         case OpCode::Type::Arithmetic: {
-            ASSERT(!instr.alu.abs_d, "unimplemented");
+            ASSERT(!instr.alu.abs_d);
 
             std::string dest = GetRegister(instr.gpr0);
             std::string op_a = instr.alu.negate_a ? "-" : "";