Host include paths from pkg-config not used when FEATURE_webengine_system_icu=On when cross-compiling

# python3 ./src/3rdparty/chromium/build/config/linux/pkg-config.py -p ../../build/qtwebengine/src/pdf/pkg-config-host_wrapper.sh icu-i18n
[["/opt/emlix/test/include"], [], ["icui18n", "icuuc", "icudata"], ["/opt/emlix/test/lib"]]

/usr/bin/c++ -MMD -MF v8/obj/v8/gen-regexp-special-case/gen-regexp-special-case.o.d -DUSE_UDEV -DUSE_AURA=1 -DUSE_OZONE=1 -DOFFICIAL_BUILD -DTOOLKIT_QT -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -DNO_UNWIND_TABLES -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DV8_TYPED_ARRAY_MAX_SIZE_IN_HEAP=64 -DV8_INTL_SUPPORT -DV8_ATOMIC_OBJECT_FIELD_WRITES -DV8_ENABLE_LAZY_SOURCE_POSITIONS -DV8_SHARED_RO_HEAP -DV8_WIN64_UNWINDING_INFO -DV8_ENABLE_REGEXP_INTERPRETER_THREADED_DISPATCH -DV8_ENABLE_WEBASSEMBLY -DV8_ALLOCATION_FOLDING -DV8_ALLOCATION_SITE_TRACKING -DV8_ADVANCED_BIGINT_ALGORITHMS -DV8_DEPRECATION_WARNINGS -DV8_TARGET_ARCH_ARM -DCAN_USE_ARMV7_INSTRUCTIONS -DCAN_USE_VFP3_INSTRUCTIONS -DCAN_USE_VFP32DREGS -DCAN_USE_NEON -DUSE_EABI_HARDFLOAT=1 -DV8_HAVE_TARGET_OS -DV8_TARGET_OS_LINUX -DUSING_SYSTEM_ICU=1 -DICU_UTIL_DATA_IMPL=ICU_UTIL_DATA_STATIC -Iv8/gen -I../../../../../../qt-everywhere-src-6.4.2/qtwebengine/src/3rdparty/chromium -I../../../../../../qt-everywhere-src-6.4.2/qtwebengine/src/3rdparty/chromium/v8 -I../../../../../../qt-everywhere-src-6.4.2/qtwebengine/src/3rdparty/chromium/v8/include -Iv8/gen/v8 -Iv8/gen/v8/include -Wall -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -Wno-unused-local-typedefs -Wno-maybe-uninitialized -Wno-deprecated-declarations -fno-delete-null-pointer-checks -Wno-comments -Wno-packed-not-aligned -Wno-dangling-else -Wno-missing-field-initializers -Wno-unused-parameter -fno-ident -fno-strict-aliasing --param=ssp-buffer-size=4 -fstack-protector -Wno-unknown-pragmas -Wno-parentheses -Wno-sign-compare -Wno-stringop-overflow -Wno-stringop-overread -Wno-psabi -Wno-multichar -Wno-format-zero-length -fno-unwind-tables -fno-asynchronous-unwind-tables -fPIC -pipe -pthread -m32 -mfpmath=sse -msse3 -fno-omit-frame-pointer -fvisibility=hidden -Wno-strict-overflow -Wno-return-type -Wno-int-in-bool-context -O3 -fdata-sections -ffunction-sections -g0 -Wno-narrowing -Wno-class-memaccess -Wno-attributes -Wno-class-memaccess -Wno-subobject-linkage -Wno-invalid-offsetof -Wno-return-type -Wno-deprecated-copy -std=gnu++17 -fno-aligned-new -fno-exceptions -fno-rtti -fvisibility-inlines-hidden -c ../../../../../../qt-everywhere-src-6.4.2/qtwebengine/src/3rdparty/chromium/v8/src/regexp/gen-regexp-special-case.cc -o v8/obj/v8/gen-regexp-special-case/gen-regexp-special-case.o
In file included from ../../../../../../qt-everywhere-src-6.4.2/qtwebengine/src/3rdparty/chromium/v8/src/regexp/gen-regexp-special-case.cc:11:
../../../../../../qt-everywhere-src-6.4.2/qtwebengine/src/3rdparty/chromium/v8/src/regexp/special-case.h:12:10: fatal error: unicode/uchar.h: No such file or directory
   12 | #include "unicode/uchar.h"
      |          ^~~~~~~~~~~~~~~~~