Add kiwisolver (#450)

packages/k/kiwisolver/xmake.lua

@@ -0,0 +1,39 @@
+package("kiwisolver")
+
+    set_homepage("https://kiwisolver.readthedocs.io/en/latest/")
+    set_description("Efficient C++ implementation of the Cassowary constraint solving algorithm")
+
+    add_urls("https://github.com/nucleic/kiwi/archive/refs/tags/$(version).tar.gz",
+             "https://github.com/nucleic/kiwi.git")
+    add_versions("1.3.1", "91d56ec628be2513a02c3721d4d8173416daf37c49423fe7a41a0e30c1101269")
+
+    on_install(function (package)
+        os.cp("kiwi", package:installdir("include"))
+    end)
+
+    on_test(function (package)
+        assert(package:check_cxxsnippets({test = [[
+            void test(int args, char** argv) {
+                kiwi::Solver solver;
+
+                kiwi::Variable x1("x1");
+                kiwi::Variable x2("x2");
+                kiwi::Variable xm("xm");
+
+                kiwi::Constraint constraints[] = {
+                    x1 >= 0,
+                    x2 <= 100,
+                    x2 >= x1 + 20,
+                    xm == (x1 + x2) / 2
+                };
+
+                for (auto& constraint : constraints)
+                    solver.addConstraint(constraint);
+
+                solver.addConstraint(x1 == 40 | kiwi::strength::weak);
+                solver.addEditVariable(xm, kiwi::strength::strong);
+                solver.suggestValue(xm, 60);
+                solver.updateVariables();
+            }
+        ]]}, {configs = {languages = "c++11"}, includes = "kiwi/kiwi.h"}))
+    end)