proj_cleanup(): make it release (static) memory allocated by proj_info()

Fixes #4754

Author: rouault

src/info.cpp

@@ -135,6 +135,18 @@ PJ_INFO proj_info(void) {
     return info;
 }
 
+/*****************************************************************************/
+void pj_clear_proj_info()
+/*****************************************************************************/
+/* Release memory associated to "info" singleton
+/*****************************************************************************/
+{
+    pj_acquire_lock();
+    free(const_cast<char *>(info.searchpath));
+    info.searchpath = nullptr;
+    pj_release_lock();
+}
+
 /*****************************************************************************/
 PJ_PROJ_INFO proj_pj_info(PJ *P) {
     /******************************************************************************

src/malloc.cpp

@@ -204,4 +204,5 @@ void proj_cleanup() {
     pj_clear_vgridshift_knowngrids_cache();
     pj_clear_gridshift_knowngrids_cache();
     pj_clear_sqlite_cache();
+    pj_clear_proj_info();
 }

src/proj_internal.h

@@ -1004,6 +1004,8 @@ int pj_get_suggested_operation(PJ_CONTEXT *ctx,
 const PJ_UNITS *pj_list_linear_units();
 const PJ_UNITS *pj_list_angular_units();
 
+void pj_clear_proj_info();
+
 void pj_clear_hgridshift_knowngrids_cache();
 void pj_clear_vgridshift_knowngrids_cache();
 void pj_clear_gridshift_knowngrids_cache();