Initialize spv_options in glslang_program_SPIRV_generate

This will prevent any recurrence of issues like the one addressed by
PR KhronosGroup#3364.

SPIRV/CInterface/spirv_c_interface.cpp

@@ -83,16 +83,9 @@ static EShLanguage c_shader_stage(glslang_stage_t stage)
 
 GLSLANG_EXPORT void glslang_program_SPIRV_generate(glslang_program_t* program, glslang_stage_t stage)
 {
-    glslang_spv_options_t spv_options;
-    spv_options.generate_debug_info = false;
-    spv_options.strip_debug_info = false;
-    spv_options.emit_nonsemantic_shader_debug_info = false;
-    spv_options.emit_nonsemantic_shader_debug_source = false;
+    glslang_spv_options_t spv_options {};
     spv_options.disable_optimizer = true;
-    spv_options.optimize_size = false;
-    spv_options.disassemble = false;
     spv_options.validate = true;
-    spv_options.compile_only = false;
 
     glslang_program_SPIRV_generate_with_options(program, stage, &spv_options);
 }