gxml: fix test (#104740)
gxml: fix test (#104740)

Fixes:
2022-06-29T02:50:02.7073230Z [34m==>[0m [1m/usr/bin/clang test.c -o test -I/opt/homebrew/opt/gettext/include -I/opt/homebrew/opt/libxml2/include/libxml2 -I/opt/homebrew/opt/glib/include/glib-2.0 -I/opt/homebrew/opt/glib/lib/glib-2.0/include -I/opt/homebrew/Cellar/gxml/0.20.0/include/gxml-0.20 -I/opt/homebrew/opt/libgee/include/gee-0.8 -D_REENTRANT -L/opt/homebrew/opt/gettext/lib -L/opt/homebrew/opt/glib/lib -L/opt/homebrew/opt/libgee/lib -L/opt/homebrew/opt/libxml2/lib -L/opt/homebrew/Cellar/gxml/0.20.0/lib -lgee-0.8 -lgio-2.0 -lglib-2.0 -lgobject-2.0 -lgxml-0.20 -lxml2 -lintl[0m
2022-06-29T02:50:02.7074580Z In file included from test.c:1:
2022-06-29T02:50:02.7075210Z In file included from /opt/homebrew/Cellar/gxml/0.20.0/include/gxml-0.20/gxml/gxml.h:14:
2022-06-29T02:50:02.7075800Z In file included from /opt/homebrew/opt/libxml2/include/libxml2/libxml/xpath.h:26:
2022-06-29T02:50:02.7076390Z In file included from /opt/homebrew/opt/libxml2/include/libxml2/libxml/xmlerror.h:10:
2022-06-29T02:50:02.7077000Z In file included from /opt/homebrew/opt/libxml2/include/libxml2/libxml/parser.h:812:
2022-06-29T02:50:02.7077780Z /opt/homebrew/opt/libxml2/include/libxml2/libxml/encoding.h:31:10: fatal error: 'unicode/ucnv.h' file not found
2022-06-29T02:50:02.7078320Z #include <unicode/ucnv.h>
2022-06-29T02:50:02.7078630Z          ^~~~~~~~~~~~~~~~
2022-06-29T02:50:02.7078940Z 1 error generated.
adam-moss/homebrew-core,adam-moss/homebrew-core,stgraber/homebrew-core,makigumo/homebrew-core,filcab/homebrew-core,chrisfinazzo/homebrew-core,sjackman/homebrew-core,zyedidia/homebrew-core,Homebrew/homebrew-core,filcab/homebrew-core,nbari/homebrew-core,lemzwerg/homebrew-core,nbari/homebrew-core,stgraber/homebrew-core,lemzwerg/homebrew-core,Homebrew/homebrew-core,nandub/homebrew-core,chrisfinazzo/homebrew-core,zyedidia/homebrew-core,makigumo/homebrew-core,sjackman/homebrew-core,nandub/homebrew-core