mk/make-config.sh: fix gcc 10.3.0 bug?? ..

mk/make-config.sh: fix gcc 10.3.0 bug?? ..

    gcc -Dmx_SOURCE -I./ -I/home/steffen/src/nail.git/include
      -I/tmp/.nail/y -I/home/steffen/src/nail.git/include/
      -I/home/steffen/src/nail.git/src/ -I/usr/local/include
      -O1 -g  -std=c89 -O -g -W -Wall -Wextra -Wbad-function-cast
      -Wcast-align -Wcast-qual -Wformat-security -Wformat-signedness
      -Winit-self -Wmissing-prototypes -Wshadow -Wunused
      -Wwrite-strings -Wno-long-long -pedantic
      -fno-asynchronous-unwind-tables -fno-common -fno-unwind-tables
      -fstrict-aliasing -fstrict-overflow -Wstrict-overflow=5
      -fstack-protector-strong -D_FORTIFY_SOURCE=2 -fPIE
      -Wl,-rpath=/usr/local/lib  -Wl,-z,relro -Wl,-z,now
      -Wl,-z,noexecstack -Wl,--as-needed -Wl,--enable-new-dtags
      -Wl,-rpath=/usr/local/lib -pie   -o /tmp/.nail/y/___tmp115148
    /tmp/.nail/y/___tmp115148.c -L/usr/local/lib
    /tmp/.nail/y/___tmp115148.c: In function 'main':
    /tmp/.nail/y/___tmp115148.c:5:4: warning: implicit declaration of function 'flock' [-Wimplicit-function-declaration]
        5 |    flock(3, LOCK_SH | LOCK_NB);

Note the -o. ?