Implement Precompiled Headers (#591)

When applied, this will speed up compile times dramatically.

CMakeLists.txt

@@ -240,6 +240,35 @@ ${PROJECT_SOURCE_DIR}/dDatabase/*.cpp
 ${PROJECT_SOURCE_DIR}/dDatabase/Tables/*.cpp
 )
 
+file(
+    GLOB HEADERS_DDATABASE
+    LIST_DIRECTORIES false
+    ${PROJECT_SOURCE_DIR}/dDatabase/*.h
+    ${PROJECT_SOURCE_DIR}/dDatabase/Tables/*.h
+    ${PROJECT_SOURCE_DIR}/thirdparty/SQLite/*.h
+)
+
+file(
+    GLOB HEADERS_DZONEMANAGER
+    LIST_DIRECTORIES false
+    ${PROJECT_SOURCE_DIR}/dZoneManager/*.h
+)
+
+file(
+    GLOB HEADERS_DCOMMON
+    LIST_DIRECTORIES false
+    ${PROJECT_SOURCE_DIR}/dCommon/*.h
+)
+
+file(
+    GLOB HEADERS_DGAME
+    LIST_DIRECTORIES false
+    ${PROJECT_SOURCE_DIR}/dGame/Entity.h 
+    ${PROJECT_SOURCE_DIR}/dGame/dGameMessages/GameMessages.h
+    ${PROJECT_SOURCE_DIR}/dGame/EntityManager.h
+    ${PROJECT_SOURCE_DIR}/dScripts/CppScripts.h
+)
+
 # Source Code for dNet
 file(
 GLOB SOURCES_DNET
@@ -312,6 +341,33 @@ add_executable(AuthServer ${SOURCES_AUTH})
 add_executable(MasterServer ${SOURCES_MASTER})
 add_executable(ChatServer ${SOURCES_CHAT})
 
+# Add out precompiled headers
+target_precompile_headers(
+    dGame PRIVATE 
+    ${HEADERS_DGAME}
+)
+
+target_precompile_headers(
+    dZoneManager PRIVATE 
+    ${HEADERS_DZONEMANAGER}
+)
+
+# Need to specify to use the CXX compiler language here or else we get errors including <string>.
+target_precompile_headers(
+    dDatabase PRIVATE 
+    "$<$<COMPILE_LANGUAGE:CXX>:${HEADERS_DDATABASE}>"
+)
+
+target_precompile_headers(
+    dCommon PRIVATE
+    ${HEADERS_DCOMMON}
+)
+
+target_precompile_headers(
+    tinyxml2 PRIVATE
+    "$<$<COMPILE_LANGUAGE:CXX>:${PROJECT_SOURCE_DIR}/thirdparty/tinyxml2/tinyxml2.h>"
+)
+
 # Target libraries to link to:
 target_link_libraries(WorldServer dCommon)
 target_link_libraries(WorldServer dChatFilter)