Update `struct` initializer to work with relatively older `C++`.

build_config/ci/gcc-clang.rb

@@ -28,7 +28,7 @@ MRuby::Build.new('cxx_abi') do |conf|
   conf.toolchain
 
   conf.gembox 'full-core'
-  conf.cc.flags += %w(-fpermissive)
+  conf.cc.flags += %w(-fpermissive -std=gnu++03)
   conf.compilers.each do |c|
     c.defines += %w(MRB_GC_FIXED_ARENA MRB_UTF8_STRING)
   end

mrbgems/mruby-bin-debugger/tools/mrdb/cmdmisc.c

@@ -141,7 +141,8 @@ static listcmd_parser_state*
 listcmd_parser_state_new(mrb_state *mrb)
 {
   listcmd_parser_state *st = (listcmd_parser_state*)mrb_malloc(mrb, sizeof(listcmd_parser_state));
-  *st = (listcmd_parser_state){0};
+  static const listcmd_parser_state st_zero = {0};
+  *st = st_zero;
   return st;
 }
 

mrbgems/mruby-bin-debugger/tools/mrdb/mrdb.c

@@ -186,9 +186,9 @@ static mrb_debug_context*
 mrb_debug_context_new(mrb_state *mrb)
 {
   mrb_debug_context *dbg = (mrb_debug_context*)mrb_malloc(mrb, sizeof(mrb_debug_context));
+  static const mrb_debug_context dbg_zero = {0};
 
-  *dbg = (mrb_debug_context){0};
-
+  *dbg = dbg_zero;
   dbg->xm = DBG_INIT;
   dbg->xphase = DBG_PHASE_BEFORE_RUN;
   dbg->next_bpno = 1;
@@ -225,9 +225,9 @@ static mrdb_state*
 mrdb_state_new(mrb_state *mrb)
 {
   mrdb_state *mrdb = (mrdb_state*)mrb_malloc(mrb, sizeof(mrdb_state));
+  static const mrdb_state mrdb_zero = {0};
 
-  *mrdb = (mrdb_state){0};
-
+  *mrdb = mrdb_zero;
   mrdb->dbg = mrb_debug_context_get(mrb);
   mrdb->command = (char*)mrb_malloc(mrb, MAX_COMMAND_LINE+1);
   mrdb->print_no = 1;

mrbgems/mruby-socket/src/socket.c

@@ -66,8 +66,8 @@ static const char *inet_ntop(int af, const void *src, char *dst, socklen_t cnt)
 {
   if (af == AF_INET)
   {
-    struct sockaddr_in in;
-    in = (struct sockaddr_in){0};
+    struct sockaddr_in in = {0};
+
     in.sin_family = AF_INET;
     memcpy(&in.sin_addr, src, sizeof(struct in_addr));
     getnameinfo((struct sockaddr *)&in, sizeof(struct
@@ -76,8 +76,8 @@ static const char *inet_ntop(int af, const void *src, char *dst, socklen_t cnt)
   }
   else if (af == AF_INET6)
   {
-    struct sockaddr_in6 in;
-    in = (struct sockaddr_in6){0};
+    struct sockaddr_in6 in = {0};
+
     in.sin6_family = AF_INET6;
     memcpy(&in.sin6_addr, src, sizeof(struct in_addr6));
     getnameinfo((struct sockaddr *)&in, sizeof(struct
@@ -89,9 +89,9 @@ static const char *inet_ntop(int af, const void *src, char *dst, socklen_t cnt)
 
 static int inet_pton(int af, const char *src, void *dst)
 {
-  struct addrinfo hints, *res, *ressave;
+  struct addrinfo hints = {0};
+  struct addrinfo *res, *ressave;
 
-  hints = (struct addrinfo){0};
   hints.ai_family = af;
 
   if (getaddrinfo(src, NULL, &hints, &res) != 0)
@@ -117,7 +117,7 @@ static int inet_pton(int af, const char *src, void *dst)
 static mrb_value
 mrb_addrinfo_getaddrinfo(mrb_state *mrb, mrb_value klass)
 {
-  struct addrinfo hints, *res0, *res;
+  struct addrinfo hints = {0}, *res0, *res;
   mrb_value ai, ary, family, lastai, nodename, protocol, sa, service, socktype;
   mrb_int flags;
   int arena_idx, error;
@@ -148,7 +148,6 @@ mrb_addrinfo_getaddrinfo(mrb_state *mrb, mrb_value klass)
     mrb_raise(mrb, E_TYPE_ERROR, "service must be String, Integer, or nil");
   }
 
-  hints = (struct addrinfo){0};
   hints.ai_flags = (int)flags;
 
   if (mrb_integer_p(family)) {

src/class.c

@@ -1698,8 +1698,10 @@ mrb_define_module_function(mrb_state *mrb, struct RClass *c, const char *name, m
 static void
 mc_clear(mrb_state *mrb)
 {
+  static const struct mrb_cache_entry ce_zero ={0};
+
   for (int i=0; i<MRB_METHOD_CACHE_SIZE; i++) {
-    mrb->cache[i] = (struct mrb_cache_entry){0};
+    mrb->cache[i] = ce_zero;
   }
 }