Replaced VALID_HEX, ISODIGIT & NBSP macros in string.h

- Moved them into modsecurity::utils::string to avoid polluting the
  global namespace.

src/actions/transformations/css_decode.cc

@@ -17,6 +17,7 @@
 
 #include "src/utils/string.h"
 
+using namespace modsecurity::utils::string;
 
 namespace modsecurity::actions::transformations {
 

src/actions/transformations/escape_seq_decode.cc

@@ -17,6 +17,8 @@
 
 #include "src/utils/string.h"
 
+using namespace modsecurity::utils::string;
+
 namespace modsecurity::actions::transformations {
 
 

src/actions/transformations/html_entity_decode.cc

@@ -23,6 +23,7 @@
 #include "src/compat/msvc.h"
 #endif
 
+using namespace modsecurity::utils::string;
 
 namespace modsecurity::actions::transformations {
 

src/actions/transformations/js_decode.cc

@@ -17,6 +17,7 @@
 
 #include "src/utils/string.h"
 
+using namespace modsecurity::utils::string;
 
 namespace modsecurity::actions::transformations {
 

src/actions/transformations/sql_hex_decode.cc

@@ -19,6 +19,7 @@
 
 #include "src/utils/string.h"
 
+using namespace modsecurity::utils::string;
 
 namespace modsecurity::actions::transformations {
 

src/actions/transformations/url_decode_uni.cc

@@ -18,6 +18,7 @@
 #include "modsecurity/rules_set.h"
 #include "src/utils/string.h"
 
+using namespace modsecurity::utils::string;
 
 namespace modsecurity::actions::transformations {