build: fix building with system icu 76

ICU 76 decided to reduce overlinking[^1] thus `icu-i18n` will no longer
add `icu-uc` when linking to shared libraries. This results in undefined
symbols/references when trying to build with system ICU 76.

[^1]: unicode-org/icu@199bc82

PR-URL: #55563
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

configure.py

@@ -1879,7 +1879,7 @@ def icu_download(path):
   elif with_intl == 'system-icu':
     # ICU from pkg-config.
     o['variables']['v8_enable_i18n_support'] = 1
-    pkgicu = pkg_config('icu-i18n')
+    pkgicu = pkg_config(['icu-i18n', 'icu-uc'])
     if not pkgicu[0]:
       error('''Could not load pkg-config data for "icu-i18n".
        See above errors or the README.md.''')