Do not ignore LLVM target creation errors (#1406)

Fixed compiler segmentation fault when given an invalid target triple.

src/libponyc/codegen/codegen.c

@@ -698,7 +698,7 @@ static void init_runtime(compile_t* c)
   c->personality = LLVMAddFunction(c->module, "pony_personality_v0", type);
 }
 
-static void init_module(compile_t* c, ast_t* program, pass_opt_t* opt)
+static bool init_module(compile_t* c, ast_t* program, pass_opt_t* opt)
 {
   c->opt = opt;
 
@@ -710,10 +710,6 @@ static void init_module(compile_t* c, ast_t* program, pass_opt_t* opt)
   if(builtin == NULL)
     builtin = package;
 
-  c->reach = reach_new();
-
-  c->tbaa_mds = tbaa_metadatas_new();
-
   // The name of the first package is the name of the program.
   c->filename = package_filename(package);
 
@@ -728,9 +724,13 @@ static void init_module(compile_t* c, ast_t* program, pass_opt_t* opt)
   else
     c->linkage = LLVMPrivateLinkage;
 
-  c->context = LLVMContextCreate();
   c->machine = make_machine(opt);
 
+  if(c->machine == NULL)
+    return false;
+
+  c->context = LLVMContextCreate();
+
   // Create a module.
   c->module = LLVMModuleCreateWithNameInContext(c->filename, c->context);
 
@@ -758,6 +758,11 @@ static void init_module(compile_t* c, ast_t* program, pass_opt_t* opt)
 
   // Empty frame stack.
   c->frame = NULL;
+
+  c->reach = reach_new();
+  c->tbaa_mds = tbaa_metadatas_new();
+
+  return true;
 }
 
 bool codegen_merge_runtime_bitcode(compile_t* c)
@@ -888,7 +893,9 @@ bool codegen(ast_t* program, pass_opt_t* opt)
   compile_t c;
   memset(&c, 0, sizeof(compile_t));
 
-  init_module(&c, program, opt);
+  if(!init_module(&c, program, opt))
+    return false;
+
   init_runtime(&c);
   genprim_reachable_init(&c, program);