Fix libicu build by having proper toolchain build

recipes/wip/libs/other/libicu/recipe.toml

@@ -1,52 +1,33 @@
 #TODO: promote
 [source]
-tar = "https://github.com/unicode-org/icu/releases/download/release-77-1/icu4c-77_1-src.tgz"
-blake3 = "8f51c4e4c6577b61d02921e800ddb0a2d4778addf7717eef4c5bb0e8a5582c3a"
+tar = "https://github.com/unicode-org/icu/releases/download/release-78.3/icu4c-78.3-sources.tgz"
+blake3 = "5657d84c78549f198f1335ec9d2f1de2b0ac2771fe081cbf00016370872c13f3"
 patches = ["redox.patch"]
 
 [build]
+dependencies = [
+    "host:libicu"
+]
 template = "custom"
 script = """
 DYNAMIC_INIT
 COOKBOOK_CONFIGURE="${COOKBOOK_SOURCE}/source/configure"
-mkdir -p host
-pushd host
-#TODO: easier way to build for host?
-HOST_ENV=(
-    env
-    --unset=AR
-    --unset=AS
-    --unset=CC
-    --unset=CFLAGS
-    --unset=CPPFLAGS
-    --unset=CXX
-    --unset=GNU_TARGET
-    --unset=LD
-    --unset=LDFLAGS
-    --unset=NM
-    --unset=OBJCOPY
-    --unset=OBJDUMP
-    --unset=PKG_CONFIG
-    --unset=PKG_CONFIG_ALLOW_CROSS
-    --unset=PKG_CONFIG_FOR_BUILD
-    --unset=PKG_CONFIG_LIBDIR
-    --unset=PKG_CONFIG_PATH
-    --unset=PKG_CONFIG_SYSROOT_DIR
-    --unset=PREFIX_RUSTFLAGS
-    --unset=RANLIB
-    --unset=READELF
-    --unset=STRIP
-    --unset=TARGET
-)
-"${HOST_ENV[@]}" printenv | sort
-"${HOST_ENV[@]}" "${COOKBOOK_CONFIGURE}"
-"${HOST_ENV[@]}" "${COOKBOOK_MAKE}" -j "${COOKBOOK_MAKE_JOBS}"
-popd
 COOKBOOK_CONFIGURE_FLAGS+=(
-    --with-cross-build="${COOKBOOK_BUILD}/host"
     icu_cv_host_frag=mh-linux
 )
+if [ "$TARGET" != "$COOKBOOK_HOST_TARGET" ]; then
+COOKBOOK_CONFIGURE_FLAGS+=(
+    --with-cross-build="${COOKBOOK_TOOLCHAIN}/usr"
+)
+fi
+
 # libicu uses TARGET for something else
 unset TARGET
 cookbook_configure
+
+if [ "$TARGET" != "$COOKBOOK_HOST_TARGET" ]; then
+# this is not ideal, but there's no other better way
+rsync -a ./ "${COOKBOOK_STAGE}/usr"
+fi
+
 """