[Image] App: enable precompiled header

- despite there are actually no header, this is nevertheless sensible, see the discussion in #7990

src/Mod/Image/App/CMakeLists.txt

@@ -28,6 +28,12 @@ set(Image_SRCS
     AppImage.cpp
 )
 
+if(FREECAD_USE_PCH)
+    add_definitions(-D_PreComp_)
+    GET_MSVC_PRECOMPILED_SOURCE("PreCompiled.cpp" PCH_SRCS ${Image_SRCS})
+    ADD_MSVC_PRECOMPILED_HEADER(Image PreCompiled.h PreCompiled.cpp PCH_SRCS)
+endif(FREECAD_USE_PCH)
+
 add_library(Image SHARED ${Image_SRCS})
 target_link_libraries(Image ${Image_LIBS})
 

src/Mod/Image/App/PreCompiled.cpp

@@ -20,5 +20,4 @@
  *                                                                         *
  ***************************************************************************/
 
-
 #include "PreCompiled.h"

src/Mod/Image/App/PreCompiled.h

@@ -28,21 +28,11 @@
 #ifdef _PreComp_
 /// point at which warnings of overly long specifiers disabled (needed for VC6)
 #ifdef _MSC_VER
-#	pragma warning( disable : 4251 )
-#	pragma warning( disable : 4503 )
-#	pragma warning( disable : 4786 )  // specifier longer then 255 chars
+# pragma warning(disable : 4005)
+# pragma warning(disable : 4251)
+# pragma warning(disable : 4503)
+# pragma warning(disable : 4786)// specifier longer then 255 chars
 #endif
 
-// standard
-#include <iostream>
-#include <sstream>
-#include <cstdio>
-#include <cassert>
-#include <string>
-#include <map>
-#include <vector>
-#include <set>
-#include <bitset>
-
 #endif // _PreComp_
 #endif