Use FetchContent for PugiXML

cmake/Libraries.cmake

@@ -1,3 +1,5 @@
+include(FetchContent)
+
 set(LIBEI_MIN_VERSION 1.2.1)
 set(LIBPORTAL_MIN_VERSION 0.6)
 
@@ -110,7 +112,13 @@ macro(configure_unix_libs)
     configure_xorg_libs()
     configure_wayland_libs()
 
-    find_package(pugixml REQUIRED)
+    set(FETCHCONTENT_FULLY_DISCONNECTED ON)
+    FetchContent_Declare(
+      pugixml
+      GIT_REPOSITORY https://github.com/zeux/pugixml.git
+      GIT_TAG v1.13
+    )
+    FetchContent_MakeAvailable(pugixml)
 
     find_package(PkgConfig)
     if(PKG_CONFIG_FOUND)

config.yaml

@@ -48,7 +48,6 @@ config:
           libgtk-3-dev \
           libgtest-dev \
           libgmock-dev \
-          libpugixml-dev \
           libei-dev \
           libportal-dev
         optional: [libei-dev, libportal-dev]
@@ -80,7 +79,6 @@ config:
           gtk3-devel \
           gtest-devel \
           gmock-devel \
-          pugixml-devel \
           libei-devel \
           libportal-devel
         optional: [libei-devel, libportal-devel]
@@ -126,7 +124,6 @@ config:
           gtk3-devel \
           googletest-devel \
           googlemock-devel \
-          pugixml-devel \
           libei-devel \
           libportal-devel
 
@@ -144,7 +141,6 @@ config:
           libnotify \
           libxkbfile \
           gtest \
-          pugixml \
           libei \
           libportal \
           qt6-base \