Fix gcc warning

[msteinert]

45.14 pgpcre.c: In function 'matches_internal': 45.14 pgpcre.c:140:21: warning: declaration of 'rc' shadows a previous local [-Wshadow=compatible-local] 45.14 140 | int rc; 45.14 | ^~ 45.14 pgpcre.c:118:33: note: shadowed declaration is here 45.14 118 | int rc; 45.14 | ^~

[msteinert]

This is obviously not a real issue, however the warning was causing a build failure due to -Werror in a somewhat complicated container build.