optimizer: fix compiler warnings

Define _GNU_SOURCE on Linux, to avoid warnings about pthread_setname_np being
implicitly defined.

Add parentheses around assignment as loop condition.

Set C++11 as the standard.

CMakeLists.txt

@@ -4,6 +4,8 @@ project(glsl_optimizer VERSION 0.1
                        DESCRIPTION "GLSL Optimizer"
                        LANGUAGES C CXX)
 
+set(CMAKE_CXX_STANDARD 11)
+
 include_directories(include)
 include_directories(src/mesa)
 include_directories(src/mapi)
@@ -16,6 +18,7 @@ include_directories(src/util)
 
 add_definitions(-D__STDC_FORMAT_MACROS)
 if(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
+  add_definitions(-D_GNU_SOURCE)
   add_definitions(-DHAVE_ENDIAN_H)
 endif()
 if(${CMAKE_SYSTEM_NAME} MATCHES "Windows")

src/compiler/glsl/ir_print_glsl_visitor.cpp

@@ -1922,7 +1922,7 @@ ir_print_glsl_visitor::visit(ir_typedecl_statement *ir)
 
 		// Find a variable defined by this interface, as it holds some necessary data.
 		exec_node* n = ir;
-		while (n = n->get_next()) {
+		while ((n = n->get_next())) {
 			ir_variable* v = ((ir_instruction *)n)->as_variable();
 			if (v != NULL && v->get_interface_type() == ir->type_decl) {
 				interface_var = v;