core: fix maybe-uninitialized warning

core: fix maybe-uninitialized warning

2026-05-29T13:14:20.8990848Z arm-linux-gnueabihf-gcc -Isrc/core/libsystemd-core-261.a.p -Isrc/core -I../src/core -Isrc/shared -I../src/shared -Isrc/bpf -I../src/bpf -I../src/libsystemd/sd-bus -I../src/libsystemd/sd-common -I../src/libsystemd/sd-device -I../src/libsystemd/sd-event -I../src/libsystemd/sd-future -I../src/libsystemd/sd-hwdb -I../src/libsystemd/sd-id128 -Isrc/libsystemd/sd-journal -I../src/libsystemd/sd-journal -I../src/libsystemd/sd-json -I../src/libsystemd/sd-netlink -I../src/libsystemd/sd-network -I../src/libsystemd/sd-path -I../src/libsystemd/sd-resolve -I../src/libsystemd/sd-varlink -Isrc/basic -I../src/basic -Isrc/fundamental -I../src/fundamental -Isrc/systemd -I../src/systemd -Isrc/version -I../src/version -I/usr/include/uuid -I/usr/include/json-c -I/usr/include/blkid -I/usr/include/libmount -fdiagnostics-color=always -DNDEBUG -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -Werror -std=gnu17 -O0 -Wno-missing-field-initializers -Wno-unused-parameter -Wno-nonnull-compare -Warray-bounds -Warray-bounds=2 -Wdate-time -Wendif-labels -Werror=bool-compare -Werror=discarded-qualifiers -Werror=format=2 -Werror=format-signedness -Werror=implicit-function-declaration -Werror=implicit-int -Werror=incompatible-pointer-types -Werror=int-conversion -Werror=missing-declarations -Werror=missing-prototypes -Werror=overflow -Werror=override-init -Werror=pointer-sign -Werror=return-type -Werror=sequence-point -Werror=shift-count-overflow -Werror=shift-overflow=2 -Werror=strict-flex-arrays -Werror=undef -Wfloat-equal -Wimplicit-fallthrough=5 -Winit-self -Wlogical-op -Wmissing-include-dirs -Wmissing-noreturn -Wnested-externs -Wold-style-definition -Wpointer-arith -Wredundant-decls -Wshadow -Wstrict-aliasing=2 -Wstrict-prototypes -Wsuggest-attribute=noreturn -Wunused-function -Wwrite-strings -Wzero-length-bounds -fdiagnostics-show-option -fexcess-precision=standard -fno-common -fstack-protector -fstack-protector-strong -fstrict-flex-arrays=3 -fno-math-errno --param=ssp-buffer-size=4 -Wno-unused-result -Werror=shadow -O2 -pipe -g -feliminate-unused-debug-types -fPIC -fno-strict-aliasing -fstrict-flex-arrays=1 -fvisibility=hidden -fno-omit-frame-pointer -include config.h -isystem../src/include/glibc -isystem../src/include/override -isystemsrc/include/override -isystem../src/include/uapi -fvisibility=default -MD -MQ src/core/libsystemd-core-261.a.p/unit.c.o -MF src/core/libsystemd-core-261.a.p/unit.c.o.d -o src/core/libsystemd-core-261.a.p/unit.c.o -c ../src/core/unit.c
2026-05-29T13:14:20.9001764Z ../src/core/unit.c: In function ‘unit_start_on_termination_deps’:
2026-05-29T13:14:20.9002500Z ../src/core/unit.c:2367:21: error: ‘job_mode’ may be used uninitialized [-Werror=maybe-uninitialized]
2026-05-29T13:14:20.9004088Z  2367 |                 r = manager_add_job(u->manager, JOB_START, other, job_mode, &error, /* ret= */ NULL);
2026-05-29T13:14:20.9004619Z       |                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2026-05-29T13:14:20.9005147Z ../src/core/unit.c:2341:17: note: ‘job_mode’ was declared here
2026-05-29T13:14:20.9005458Z  2341 |         JobMode job_mode;
2026-05-29T13:14:20.9005673Z       |                 ^~~~~~~~
2026-05-29T13:14:20.9005898Z cc1: all warnings being treated as errors

Follow-up for 9faeb2d024540ac4b94dedb00a13606ec262cc31