Keep shared libraries from calling main program's startup/cleanup procs on Linux

src/llvm_backend.cpp

@@ -1907,6 +1907,10 @@ gb_internal lbProcedure *lb_create_startup_runtime(lbModule *main_module, lbProc
 	lb_add_attribute_to_proc(p->module, p->value, "optnone");
 	lb_add_attribute_to_proc(p->module, p->value, "noinline");
 
+	// Make sure shared libraries call their own runtime startup on Linux.
+	LLVMSetVisibility(p->value, LLVMHiddenVisibility);
+	LLVMSetLinkage(p->value, LLVMWeakAnyLinkage);
+
 	lb_begin_procedure_body(p);
 
 	lb_setup_type_info_data(main_module);
@@ -2016,6 +2020,10 @@ gb_internal lbProcedure *lb_create_cleanup_runtime(lbModule *main_module) { // C
 	lb_add_attribute_to_proc(p->module, p->value, "optnone");
 	lb_add_attribute_to_proc(p->module, p->value, "noinline");
 
+	// Make sure shared libraries call their own runtime cleanup on Linux.
+	LLVMSetVisibility(p->value, LLVMHiddenVisibility);
+	LLVMSetLinkage(p->value, LLVMWeakAnyLinkage);
+
 	lb_begin_procedure_body(p);
 
 	CheckerInfo *info = main_module->gen->info;