Abilty to not include CPLGetSymbol when not building plugins

[schwehr]

Feature description

Before RFC 97 PR #8695 / 8821682, I was able to build without CPLGetSymbol in my custom environment that has no plugins. I'm still able to do that with some custom patches, but it would be nice to have this be a general option. The most common use case is likely for folks that are trying to run GDAL in a sandbox that restricts the syscalls that are allowed.

I would make a PR for this, but I'm guessing there would be some unintended consequences.

I don't include port/cplgetsymbol.cpp in my build and the patch I have right now is as follows for a base of 3968f9c:

diff --show-c-function -u {a,b}/gcore/gdaldrivermanager.cpp
--- a/gcore/gdaldrivermanager.cpp	2024-11-22 06:21:56.514903847 +0000
+++ b/gcore/gdaldrivermanager.cpp	2024-11-22 06:22:39.414793757 +0000
@@ -1370,6 +1370,8 @@ GDALDriver *GDALPluginDriverProxy::GetRe
     }
     else
     {
+        return nullptr;
+#if 0
         CPLString osFuncName;
         if (STARTS_WITH(m_osPluginFileName.c_str(), "gdal_"))
         {
@@ -1433,6 +1435,7 @@ GDALDriver *GDALPluginDriverProxy::GetRe
                 poDriverManager->m_oMapRealDrivers.erase(oIter);
             }
         }
+#endif
     }

     if (m_poRealDriver)

Additional context

No response

[rouault]

@schwehr I see the calls to CPLGetSymbol() that pre-existed RFC 97 are protected within the #else branch of #ifdef GDAL_NO_AUTOLOAD. Perhaps you can do a pull request for the extra calls that have been added?