assert(handle !in _handleToDSO) in setDSOForHandle fails on OSX

[timotheecour]

@Syniurge @klickverbot @ MartinNowak (since this seem to touch on druntime shared library initialization issues)

to reproduce: same test case as in #63

$calypso_D/lib/libcalypso-ldc-shared.dylib is being registered twice; depending on program, it could be another file that is registered twice;
workaround: just return from _d_dso_registry (in Calypso/runtime/druntime/src/rt/sections_elf_shared.d) when input corresponds to a so already registered.

Here is where it would fail:

#in void setDSOForHandle(DSO* pdso, void* handle):
assert(handle !in _handleToDSO); // fails

not sure if the fix is good enough though, doesn't seem so based on other bug i have after that

[timotheecour]

TODO:do a PR

Calypso/runtime/druntime/src/rt/sections_elf_shared.d:

 extern(C) void _d_dso_registry(void* arg)
 {
+    static int counter=0;
+    counter++;
+    {
+        auto data2 = cast(CompilerDSOData*)arg;
+        Dl_info info = void;
+        if(dladdr(data2._slot, &info) == 0){
+            assert(0);
+        }
+        assert(dladdr(data2._slot, &info) != 0);
+        printf("c:%d arg:%p name:%s\n", counter, arg, info.dli_fname);
+        auto name2=info.dli_fname;
+
+        // IMPROVE
+        alias string2=char[256];
+        __gshared string2[10] names;
+
+        __gshared size_t names_length=0;
+        __gshared is_first=true;
+        if(is_first){
+            foreach(ai;names){
+                ai="";
+            }
+            is_first=false;
+        }
+        import core.stdc.string:strlen;
+        import core.stdc.string:strcmp;
+        foreach(namei; names){
+            const(char*)namei2=namei.ptr;
+            auto tmp=strcmp(namei2, name2);
+            if(tmp==0){
+                printf("WORKAROUND:RETURN\n");
+                return;
+            }
+        }
+        assert(names_length<names.length);
+        names[names_length][0..strlen(name2)][]=name2[0..strlen(name2)];
+        names[names_length][strlen(name2)]=0;
+        names_length++;
+    }
+
     auto data = cast(CompilerDSOData*)arg;

[Syniurge]

This assert was the cause of #60.