Revert: mongoose: no declspec(dllimport) for static data

This (partly) reverts 7c5caf6

Static members of a class can be accessed without instantiating the
class:
https://en.cppreference.com/w/cpp/language/static
That is conceptionally different from static data. They require
`dllexport`/`dllimport` attributes to be correctly exported from dlls
using MSVC.

Mongoose/Include/Mongoose_Logger.hpp

@@ -103,10 +103,10 @@ typedef enum TimingType
 class Logger
 {
 private:
-    /* MONGOOSE_API */ static int debugLevel;
-    /* MONGOOSE_API */ static bool timingOn;
-    /* MONGOOSE_API */ static double clocks[6];
-    /* MONGOOSE_API */ static float times[6];
+    MONGOOSE_API static int debugLevel;
+    MONGOOSE_API static bool timingOn;
+    MONGOOSE_API static double clocks[6];
+    MONGOOSE_API static float times[6];
 
 public:
     static inline void tic(TimingType timingType);