Add support for overlays (still needs a custom pmm to work)

include/cmake.hpp

@@ -34,7 +34,11 @@ struct Package {
 
 struct Vcpkg {
     std::string version;
+    std::string triplet;
     std::vector<std::string> packages;
+    std::vector<std::string> ports;
+    std::vector<std::string> overlay_ports;
+    std::vector<std::string> overlay_triplets;
 };
 
 enum TargetType {

src/cmake.cpp

@@ -33,6 +33,7 @@ static EnumType to_enum(const std::string &str, const std::string &help_name) {
     return value;
 }
 
+// If the key is found, get strongly-typed value (throws on user-error)
 template <typename T>
 static void get_optional(const TomlBasicValue &v, const toml::key &ky, T &destination);
 
@@ -249,6 +250,8 @@ CMake::CMake(const std::string &path, bool build) {
             const auto &v = toml::find(toml, "vcpkg");
             vcpkg.version = toml::find(v, "version").as_string();
             vcpkg.packages = toml::find<decltype(vcpkg.packages)>(v, "packages");
+            get_optional(v, "overlay-ports", vcpkg.overlay_ports);
+            get_optional(v, "overlay-triplets", vcpkg.overlay_triplets);
 
             // This allows the user to use a custom pmm version if desired
             if (contents.count("pmm") == 0) {

src/gen.cpp

@@ -526,7 +526,11 @@ int generate_cmake(const char *path, bool root) {
         cmd("include")("${pmm_SOURCE_DIR}/pmm.cmake");
         tsl::ordered_map<std::string, std::vector<std::string>> vcpkg_args;
         vcpkg_args["REVISION"] = {cmake.vcpkg.version};
+        vcpkg_args["TRIPLET"] = {cmake.vcpkg.triplet};
         vcpkg_args["REQUIRES"] = cmake.vcpkg.packages;
+        vcpkg_args["PORTS"] = cmake.vcpkg.ports;
+        vcpkg_args["OVERLAY_PORTS"] = cmake.vcpkg.overlay_ports;
+        vcpkg_args["OVERLAY_TRIPLETS"] = cmake.vcpkg.overlay_triplets;
         auto vcpkg = std::make_pair("VCPKG", vcpkg_args);
         cmd("pmm")(vcpkg).endl();
     }