baresip: fix compilation with NLS

baresip: fix compilation with NLS

Fixes issue:

/master/build/staging_dir/toolchain-arm_cortex-a9+vfpv3-d16_gcc-11.2.0_musl_eabi/lib/gcc/arm-openwrt-linux-muslgnueabi/11.2.0/../../../../arm-openwrt-linux-muslgnueabi/bin/ld: cannot find -lintl
  LD [M]  speex_pp.so
  LD [M]  stdio.so
collect2: error: ld returned 1 exit status
  LD [M]  syslog.so
make[3]: *** [mk/mod.mk:41: gst.so] Error 1
make[3]: *** Waiting for unfinished jobs....
make[3]: Leaving directory '/master/build/build_dir/target-arm_cortex-a9+vfpv3-d16_musl_eabi/baresip-1.1.0'

Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>