pkg-config extension

HConfig

@@ -1,5 +1,6 @@
 grbc_want_version("1.0")
 grbc_load_platform("platform.hcfg")
+grbc_ext("GRBC_EXT_pkg_config")
 
 local grbc_pkg_config_ext = grbc_library(LibraryConfig.new({
     name = "libgrbc_pkg_config",
@@ -74,12 +75,7 @@ local grbc_exe = grbc_executable(ExecutableConfig.new({
     },
 
     requirements = {
-        Package.new({
-            name = "lua",
-            compiler_flags = "",
-            linker_flags = "-llua -lm -ldl"
-        }),
-
+        grbc_pkg_config("lua"),
         grbc_pkg("libgrbc"),
         grbc_pkg("libgrbc_pkg_config")
     },