Split the dependencies.py file into several parts.

kiwixbuild/dependencies/libzim.py

@@ -0,0 +1,22 @@
+from .base import (
+    Dependency,
+    GitClone,
+    MesonBuilder)
+
+class Libzim(Dependency):
+    name = "libzim"
+
+    @property
+    def dependencies(self):
+        base_dependencies = ['zlib', 'lzma', 'xapian-core']
+        if self.buildEnv.platform_info.build != 'native':
+            return base_dependencies + ["icu4c_cross-compile"]
+        else:
+            return base_dependencies + ["icu4c"]
+
+    class Source(GitClone):
+        git_remote = "https://github.com/openzim/libzim.git"
+        git_dir = "libzim"
+
+    class Builder(MesonBuilder):
+        test_option = "-t 8"