Merge pull request OSGeo#5973 from rouault/fix_5970

netCDF: fix 2 issues with netCDF 4.9.0 of msys2-mingw64 (fixes OSGeo#5970)

frmts/netcdf/netcdfdataset.cpp

@@ -75,8 +75,12 @@
 
 #define ROTATED_POLE_VAR_NAME "rotated_pole"
 
-// Detect netCDF 4.8
-#ifdef NC_ENCZARR
+// netCDF 4.8 switched to expecting filenames in UTF-8 on Windows
+// But with netCDF 4.9 and https://github.com/Unidata/netcdf-c/pull/2277/,
+// this is apparently back to expecting filenames in current codepage...
+// Detect netCDF 4.8 with NC_ENCZARR
+// Detect netCDF 4.9 with NC_NOATTCREORD
+#if defined(NC_ENCZARR) && !defined(NC_NOATTCREORD)
 #define NETCDF_USES_UTF8
 #endif
 
@@ -9412,6 +9416,25 @@ netCDFDataset::CreateLL( const char *pszFilename,
     }
 #endif
 
+#if defined(WIN32)
+    {
+        // Works around bug of msys2 netCDF 4.9.0 package where nc_create() crashes
+        VSIStatBuf sStat;
+        const char* pszDir = CPLGetDirname(osFilenameForNCCreate.c_str());
+        if( VSIStat(pszDir, &sStat) != 0 )
+        {
+            CPLError(CE_Failure, CPLE_OpenFailed,
+                     "Unable to create netCDF file %s: non existing output directory",
+                     pszFilename);
+            CPLReleaseMutex(hNCMutex);  // Release mutex otherwise we'll deadlock
+                                        // with GDALDataset own mutex.
+            delete poDS;
+            CPLAcquireMutex(hNCMutex, 1000.0);
+            return nullptr;
+        }
+    }
+#endif
+
     int status = nc_create(osFilenameForNCCreate, poDS->nCreateMode, &(poDS->cdfid));
 
     // Put into define mode.