Poll all text from linux global hotkeys instead of once per update

src/GlobalHotkeysLinux.cpp

@@ -89,13 +89,14 @@ namespace gsr {
         }
 
         char buffer[256];
+        while(true) {
             char *line = fgets(buffer, sizeof(buffer), read_file);
             if(!line)
-            return;
+                break;
 
             const int line_len = strlen(line);
             if(line_len == 0)
-            return;
+                continue;
 
             if(line[line_len - 1] == '\n')
                 line[line_len - 1] = '\0';
@@ -106,3 +107,4 @@ namespace gsr {
                 it->second(action);
         }
     }
+}