freeglut: Use the mesa-glu package when not on Apple or Windows

The glu/system package installs the Mesa GLU system package on Linux and FreeBSD.
Now that the mesa-glu package is available in Conan, use that instead.

recipes/freeglut/all/conanfile.py

@@ -1,5 +1,6 @@
 from conan import ConanFile
 from conan.errors import ConanInvalidConfiguration
+from conan.tools.apple import is_apple_os
 from conan.tools.cmake import CMake, CMakeToolchain, cmake_layout
 from conan.tools.files import collect_libs, copy, get, rmdir
 from conan.tools.scm import Version
@@ -49,7 +50,10 @@ def layout(self):
 
     def requirements(self):
         self.requires("opengl/system")
-        self.requires("glu/system")
+        if is_apple_os(self) or self.settings.os == "Windows":
+            self.requires("glu/system")
+        else:
+            self.requires("mesa-glu/9.0.3")
         if self.settings.os == "Linux":
             self.requires("xorg/system")
 
@@ -124,6 +128,10 @@ def package_info(self):
         self.cpp_info.components["freeglut_"].names["cmake_find_package_multi"] = config_target
         self.cpp_info.components["freeglut_"].set_property("cmake_target_name", f"FreeGLUT::{config_target}")
         self.cpp_info.components["freeglut_"].set_property("pkg_config_name", pkg_config)
-        self.cpp_info.components["freeglut_"].requires.extend(["opengl::opengl", "glu::glu"])
+        self.cpp_info.components["freeglut_"].requires.append("opengl::opengl")
+        if is_apple_os(self) or self.settings.os == "Windows":
+            self.cpp_info.components["freeglut_"].requires.append("glu::glu")
+        else:
+            self.cpp_info.components["freeglut_"].requires.append("mesa-glu::mesa-glu")
         if self.settings.os == "Linux":
             self.cpp_info.components["freeglut_"].requires.append("xorg::xorg")