Infrastructure for compiler-specific options

* Add file cmake/CompilerOptions.cmake for setting up compiler
  specific options
* Disable 'missing-braces' warning on Clang
* Avoid defect in g++ 4.9.2 standard library that omits move
  constructor for `stdd::ifstream`
* Remove signed/unsigned warning in test_optional.cpp

CMakeLists.txt

@@ -8,7 +8,10 @@ enable_language(CXX)
 set(SAVED_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
 
 # compilation flags
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -std=c++11 -pthread -Wall")
+set(CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake")
+include("CompilerOptions")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CXXOPT_DEBUG} ${CXXOPT_CXX11} ${CXXOPT_PTHREAD} ${CXXOPT_WALL}")
+# -g -std=c++11 -pthread -Wall")
 
 # this generates a .json file with full compilation command for each file
 set(CMAKE_EXPORT_COMPILE_COMMANDS "YES")

cmake/CompilerOptions.cmake

+# Compiler-aware compiler options
+
+set(CXXOPT_DEBUG "-g")
+set(CXXOPT_PTHREAD "-pthread")
+set(CXXOPT_CXX11 "-std=c++11")
+set(CXXOPT_WALL "-Wall")
+
+if(${CMAKE_CXX_COMPILER_ID} MATCHES "Clang")
+    # Disable 'missing-braces' warning: this will inappropriately
+    # flag initializations such as
+    #     std::array<int,3> a={1,2,3};
+
+    set(CXXOPT_WALL "${CXXOPT_WALL} -Wno-missing-braces")
+endif()

tests/test_optional.cpp

@@ -7,7 +7,7 @@
 
 #if defined(__clang__)
 // refer: https://llvm.org/bugs/show_bug.cgi?id=21629
-#pragma clang diagnostic ignored "-Wmissing-braces"
+//#pragma clang diagnostic ignored "-Wmissing-braces"
 #endif
 
 using namespace nest::mc::util;
@@ -66,7 +66,7 @@ TEST(optionalm,deref) {
 
 TEST(optionalm,ctor_conv) {
     optional<std::array<int,3>> x{{1,2,3}};
-    EXPECT_EQ(3,x->size());
+    EXPECT_EQ(3u,x->size());
 }
 
 TEST(optionalm,ctor_ref) {

tests/util.hpp

@@ -60,7 +60,7 @@ nlohmann::json
 load_spike_data(const std::string& input_name)
 {
     nlohmann::json cell_data;
-    auto fid = std::ifstream(input_name);
+    std::ifstream fid(input_name);
     if(!fid.is_open()) {
         std::cerr << "error : unable to open file " << input_name
                   << " : run the validation generation script first\n";