fixes #6096

compiler/jsgen.nim

@@ -2340,7 +2340,7 @@ proc gen(p: PProc, n: PNode, r: var TCompRes) =
   of nkPragma: genPragma(p, n)
   of nkProcDef, nkMethodDef, nkConverterDef:
     var s = n.sons[namePos].sym
-    if sfExportc in s.flags and compilingLib:
+    if {sfExportc, sfCompilerProc} * s.flags == {sfExportc}:
       genSym(p, n.sons[namePos], r)
       r.res = nil
   of nkGotoState, nkState:

lib/system/jssys.nim

@@ -157,10 +157,10 @@ proc reraiseException() {.compilerproc, asmNoStackFrame.} =
 
     asm "throw lastJSError;"
 
-proc raiseOverflow {.exportc: "raiseOverflow", noreturn.} =
+proc raiseOverflow {.exportc: "raiseOverflow", noreturn, compilerProc.} =
   raise newException(OverflowError, "over- or underflow")
 
-proc raiseDivByZero {.exportc: "raiseDivByZero", noreturn.} =
+proc raiseDivByZero {.exportc: "raiseDivByZero", noreturn, compilerProc.} =
   raise newException(DivByZeroError, "division by zero")
 
 proc raiseRangeError() {.compilerproc, noreturn.} =