pgsql: Silence compiler warnings on clang 21

Silence compiler warnings on clang 21

Clang 21 shows some new compiler warnings, for example:

warning: variable 'dstsize' is uninitialized when passed as a const pointer argument here [-Wuninitialized-const-pointer]

The fix is to initialize the variables when they are defined. This is
similar to, for example, the existing situation in gistKeyIsEQ().

Discussion: /messages/by-id/6604ad6e-5934-43ac-8590-15113d6ae4b1@eisentraut.org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/e92677e86333562b8dd4972083c8a1abf985d90d

Modified Files
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src/backend/access/common/toast_internals.c | 2 +-
src/backend/access/gist/gistutil.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)