Add non-POSIX dlfcn extensions for Darwin, add const to dladdr

src/core/sys/darwin/dlfcn.d

@@ -0,0 +1,40 @@
+/**
+ * D header file for Darwin.
+ *
+ * $(LINK2 https://opensource.apple.com/source/dyld/dyld-360.22/include/dlfcn.h, Apple dyld/dlfcn.h)
+ *
+ * Copyright: Copyright David Nadlinger 2016.
+ * License:   $(WEB www.boost.org/LICENSE_1_0.txt, Boost License 1.0).
+ * Authors:   David Nadlinger
+ */
+module core.sys.darwin.dlfcn;
+
+version (OSX)
+    version = Darwin;
+else version (iOS)
+    version = Darwin;
+else version (TVOS)
+    version = Darwin;
+else version (WatchOS)
+    version = Darwin;
+
+version (Darwin):
+extern(C):
+nothrow:
+@nogc:
+
+public import core.sys.posix.dlfcn;
+
+struct Dl_info
+{
+    const(char)* dli_fname;
+    void*        dli_fbase;
+    const(char)* dli_sname;
+    void*        dli_saddr;
+}
+
+int dladdr(in void* addr, Dl_info* info);
+
+enum RTLD_NOLOAD = 0x10;
+enum RTLD_NODELETE = 0x80;
+enum RTLD_FIRST = 0x100;

src/core/sys/linux/dlfcn.d

@@ -265,7 +265,7 @@ static if (__USE_GNU)
         void* dli_saddr;
     }
 
-    int dladdr(void* __address, Dl_info* __info);
+    int dladdr(in void* __address, Dl_info* __info);
     int dladdr1(void* __address, Dl_info* __info, void** __extra_info, int __flags);
 
     enum

src/core/sys/posix/dlfcn.d

@@ -120,7 +120,7 @@ version( CRuntime_Glibc )
 
     deprecated("Please use core.sys.linux.dlfcn for non-POSIX extensions")
     {
-        int   dladdr(void* addr, Dl_info* info);
+        int   dladdr(in void* addr, Dl_info* info);
         void* dlvsym(void* handle, in char* symbol, in char* version_);
 
         struct Dl_info