lapwing just spit up a possibly relevant issue:
ccache gcc -std=gnu99 -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Werror=vla
-Wendif-labels-Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard -g
-O2-Werror -fPIC -I. -I. -I../../src/include -DENFORCE_REGRESSION_TEST_NAME_RESTRICTIONS -D_GNU_SOURCE
-I/usr/include/libxml2 -I/usr/include/et -c -o verify_heapam.o verify_heapam.c
verify_heapam.c: In function 'get_xid_status':
verify_heapam.c:1432:5: error: 'fxid.value' may be used uninitialized in this function [-Werror=maybe-uninitialized]
cc1: all warnings being treated as errors
