Update CMakeLists.txt,单独编译库时，不破坏当前环境；当MESA_SHARED_INSTALL_DIR变量被定义时，会将生成的库文件安装MESA_SHARED_INSTALL_DIR定义的路径下

CMakeLists.txt

@@ -37,7 +37,11 @@ file(GLOB SRC
 
 # Shared Library Output
 add_library(${lib_name}_shared SHARED ${SRC})
-set_target_properties(${lib_name}_shared PROPERTIES OUTPUT_NAME ${lib_name})
+if(DEFINED MESA_SHARED_INSTALL_DIR)
+	set_target_properties(${lib_name}_shared PROPERTIES OUTPUT_NAME ${lib_name} LIBRARY_OUTPUT_DIRECTORY ${MESA_SHARED_INSTALL_DIR})
+else()
+	set_target_properties(${lib_name}_shared PROPERTIES OUTPUT_NAME ${lib_name})
+endif()
 
 # static Library Output
 add_library(${lib_name}_static STATIC ${SRC})