bug#63526: hubbub build failure when doing guix package -u

[Andy Tai <atai@atai.org>]

key lines:

COMPILE: test/tokeniser2.c
 COMPILE: test/tokeniser3.c
 COMPILE: test/tree.c
 COMPILE: test/tree2.c
 COMPILE: test/tree-buf.c
test/tokeniser2.c: In function ‘token_handler’:
test/tokeniser2.c:444:46: error: ‘t.data.character.ptr’ may be used
uninitialized [-Werror=maybe-uninitialized]
  444 |                         t.data.character.ptr += len;
      |                                              ^~
test/tokeniser2.c:441:38: note: ‘t’ declared here
  441 |                         hubbub_token t;
      |                                      ^
test/tokeniser2.c:445:46: error: ‘t.data.character.len’ may be used
uninitialized [-Werror=maybe-uninitialized]
  445 |                         t.data.character.len -= len;
      |                                              ^~
test/tokeniser2.c:441:38: note: ‘t’ declared here
  441 |                         hubbub_token t;
      |                                      ^
test/tokeniser3.c: In function ‘token_handler’:
test/tokeniser3.c:453:46: error: ‘t.data.character.ptr’ may be used
uninitialized [-Werror=maybe-uninitialized]
  453 |                         t.data.character.ptr += len;
      |                                              ^~
test/tokeniser3.c:450:38: note: ‘t’ declared here
  450 |                         hubbub_token t;
      |                                      ^
test/tokeniser3.c:454:46: error: ‘t.data.character.len’ may be used
uninitialized [-Werror=maybe-uninitialized]
  454 |                         t.data.character.len -= len;
      |                                              ^~
test/tokeniser3.c:450:38: note: ‘t’ declared here
  450 |                         hubbub_token t;
      |                                      ^
    LINK: build-x86_64-unknown-linux-gnu-x86_64-unknown-linux-gnu-release-lib-shared/test_entities
    LINK: build-x86_64-unknown-linux-gnu-x86_64-unknown-linux-gnu-release-lib-shared/test_csdetect
    LINK: build-x86_64-unknown-linux-gnu-x86_64-unknown-linux-gnu-release-lib-shared/test_tokeniser
    LINK: build-x86_64-unknown-linux-gnu-x86_64-unknown-linux-gnu-release-lib-shared/test_parser
cc1: all warnings being treated as errors
make: *** [/gnu/store/3jqaqf59ra550lk7hvpgpg8l5krxizra-netsurf-buildsystem-1.9/share/netsurf-buildsystem/makefiles/Makefile.top:631:
build-x86_64-unknown-linux-gnu-x86_64-unknown-linux-gnu-release-lib-shared/test_tokeniser2.o]
Error 1
make: *** Waiting for unfinished jobs....
cc1: all warnings being treated as errors
make: *** [/gnu/store/3jqaqf59ra550lk7hvpgpg8l5krxizra-netsurf-buildsystem-1.9/share/netsurf-buildsystem/makefiles/Makefile.top:631:
build-x86_64-unknown-linux-gnu-x86_64-unknown-linux-gnu-release-lib-shared/test_tokeniser3.o]
Error 1

Test suite failed, dumping logs.
error: in phase 'check': uncaught exception:
%exception #<&invoke-error program: "make" arguments: ("test" "-j"
"31" "COMPONENT_TYPE=lib-shared" "CC=gcc" "BUILD_CC=gcc"
"PREFIX=/gnu/store/7fn6jxg1vpadm8rpa8rzbwqgipxlwync-hubbub-0.3.7"
"NSSHARED=/gnu/store/3jqaqf59ra550lk7hvpgpg8l5krxizra-netsurf-buildsystem-1.9/share/netsurf-buildsystem")
exit-status: 2 term-signal: #f stop-signal: #f>
phase `check' failed after 0.2 seconds
command "make" "test" "-j" "31" "COMPONENT_TYPE=lib-shared" "CC=gcc"
"BUILD_CC=gcc" "PREFIX=/gnu/store/7fn6jxg1vpadm8rpa8rzbwqgipxlwync-hubbub-0.3.7"
"NSSHARED=/gnu/store/3jqaqf59ra550lk7hvpgpg8l5krxizra-netsurf-buildsystem-1.9/share/netsurf-buildsystem"
failed with status 2