Correctly build ICU data when building for wasm.

When we use `--disable-tools` (ie, when we are cross-compiling), ICU
will build the data only if it detects we are cross-compiling.

This make sens until we cross-compiling for wasm.
Wasm output is a script file with the interpreter in the sdk we have
installed. So ICU's configure can run the test binary and so doesn't detect
we are cross-compiling.

So we have to patch ICU Makefile to make it build the ICU data anyway.

kiwixbuild/dependencies/base.py

@@ -283,6 +283,8 @@ class Builder:
         if hasattr(self, '_pre_build_script'):
             self.command('pre_build_script', self._pre_build_script)
         self.command('configure', self._configure)
+        if hasattr(self, '_post_configure_script'):
+            self.command('post_configure_script', self._post_configure_script)
         self.command('compile', self._compile)
         if hasattr(self, '_test'):
             self.command('test', self._test)

kiwixbuild/dependencies/icu4c.py

@@ -7,6 +7,7 @@ from .base import (
 from kiwixbuild.utils import pj, SkipCommand, Remotefile, extract_archive
 from kiwixbuild._global import get_target_step, neutralEnv
 import os, shutil
+import fileinput
 
 class Icu(Dependency):
     name = "icu4c"
@@ -77,3 +78,13 @@ class Icu(Dependency):
 
         def set_env(self, env):
             env['ICU_DATA_FILTER_FILE'] = pj(os.path.dirname(os.path.realpath(__file__)), "icu4c_data_filter.json")
+
+        def _post_configure_script(self, context):
+            if self.buildEnv.platformInfo.build != "wasm":
+                context.skip()
+            context.try_skip(self.build_path)
+            for line in fileinput.input(pj(self.build_path, 'Makefile'), inplace=True):
+                if line == "#DATASUBDIR = data\n":
+                    print("DATASUBDIR = data")
+                else:
+                    print(line, end="")

kiwixbuild/utils.py

@@ -189,6 +189,9 @@ class Context:
         self.autoskip_file = None
         self.no_skip = False
 
+    def skip(self, msg=""):
+        raise SkipCommand(msg)
+
     def try_skip(self, path, extra_name=""):
         if self.no_skip:
             return