[FFmpeg-user] how to compile ffmpeg with some arguments in bash script file?

[Bang He]

my operating system is ubuntu-22.04-desktop-amd64.iso

bash script file is 'compile.sh'. content of the file is bellow:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
#!/bin/bash

## set some flags
DEBUG_FLAG='--extra-cflags="-g -O0" --extra-cxxflags="-g -O0"'

CC="gcc" CXX="g++" LD="ld" AR="ar" CCAS="gcc -c" RANLIB="ranlib"
STRIP="strip" ./configure $DEBUG_FLAG
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when i run it: ./compile.sh, error happen:
./configure: 1: eval: Syntax error: Unterminated quoted string


What should I do now?