Añadir soporte para clean

Signed-off-by: somebody_master <somebody_master@somebodyserver.mooo.com>

build/build.sh

@@ -1,5 +1,10 @@
 #!/usr/bin/env bash
 
+function clean() {
+    cd gdextension || return 1
+    scons --clean
+}
+
 function build() {
     cd gdextension || return 1
     scons
@@ -25,13 +30,14 @@ function build_db() {
     cd ..
 }
 
-while getopts "bdh" flag; do
+while getopts "bdch" flag; do
     case "$flag" in
         d) build_db ;;
         b) build ;;
-        h) echo "Use -b for build or -d for generating a compile_commands.json" ;;
+        c) clean ;;
+        h) echo "Use -b for build , -d for generating a compile_commands.json or -c for cleaning" ;;
         ?)
-            echo "script usage: $(basename \$0) [-b] [-d] [-h]" >&2
+            echo "script usage: $(basename \$0) [-b] [-d] [-c] [-h]" >&2
             exit 1
             ;;
     esac