DLL fixes for windows; fixes #175

compiler/cgen.nim

@@ -861,7 +861,8 @@ proc genMainProc(m: BModule) =
         CommonMainBody & "}$n"
     WinCDllMain = 
         "BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fwdreason, $n" &
-        "                    LPVOID lpvReserved) {$n" & "\tNimMain();$n" &
+        "                    LPVOID lpvReserved) {$n" &
+          "\tif(fwdreason == DLL_PROCESS_ATTACH) NimMain();$n" &
         "\treturn 1;$n" & "}$n"
     PosixNimDllMain = WinNimDllMain
     PosixCDllMain = 

compiler/pragmas.nim

@@ -215,12 +215,18 @@ proc processDynLib(c: PContext, n: PNode, sym: PSym) =
   if (sym == nil) or (sym.kind == skModule):
     POptionEntry(c.optionStack.tail).dynlib = getLib(c, libDynamic, 
         expectDynlibNode(c, n))
-  elif n.kind == nkExprColonExpr: 
+  else:
+    if n.kind == nkExprColonExpr:
       var lib = getLib(c, libDynamic, expectDynlibNode(c, n))
       addToLib(lib, sym)
       incl(sym.loc.flags, lfDynamicLib)
     else:
       incl(sym.loc.flags, lfExportLib)
+    # since we'll be loading the dynlib symbols dynamically, we must use
+    # a calling convention that doesn't introduce custom name mangling
+    # cdecl is the default - the use can override this explicitly
+    if sym.typ.callConv == ccDefault:
+      sym.typ.callConv = ccCDecl
 
 proc processNote(c: PContext, n: PNode) =
   if (n.kind == nkExprColonExpr) and (sonsLen(n) == 2) and

lib/system.nim

@@ -1935,7 +1935,6 @@ when not defined(EcmaScript) and not defined(NimrodVM):
     include "system/syslocks"
     include "system/threads"
   elif not defined(nogc):
-    initStackBottom()
     initGC()
 
   proc setControlCHook*(hook: proc () {.noconv.})

lib/system/threads.nim

@@ -203,7 +203,6 @@ when not defined(useNimRtl):
   when not useStackMaskHack:
     var mainThread: TGcThread
     ThreadVarSetValue(globalsSlot, addr(mainThread))
-    initStackBottom()
     initGC()
     
   when emulatedThreadVars: