upgs: Remove extra _DEFAULT_SOURCE definition
This extra _DEFAULT_SOURCE definition results in a double definition
which is a compile error.
This fixes the following compile error with glibc:
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ugps-2019-06-25-cd7eabcd/nmea.c:19: error: "_DEFAULT_SOURCE" redefined [-Werror]
#define _DEFAULT_SOURCE
<command-line>: note: this is the location of the previous definition
cc1: all warnings being treated as errors
Signed-off-by: Hauke Mehrtens <[email protected]>
Hauke Mehrtens