Don't use our copy of libpng header files when USE_SHARED_LIBPNG is ON

CMakeLists.txt

@@ -112,14 +112,6 @@ set(SIMPLEINI_DIR       ${CMAKE_SOURCE_DIR}/third_party/simpleini)
 set(TINYXML_DIR         ${CMAKE_SOURCE_DIR}/third_party/tinyxml)
 set(ZLIB_DIR            ${CMAKE_SOURCE_DIR}/third_party/zlib)
 
-# Zlib generated zconf.h file
-include_directories(${CMAKE_BINARY_DIR}/third_party/zlib)
-
-# We need private libpng header files so it doesn't matter if we use
-# the shared version of libpng or not, we need to find header files in
-# "third_party/libpng"" directory.
-include_directories(${LIBPNG_DIR})
-
 # Search in the "cmake" directory for additional CMake modules.
 list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake)
 
@@ -127,10 +119,7 @@ list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake)
 set(LIBRARY_OUTPUT_PATH ${CMAKE_BINARY_DIR}/lib)
 
 ######################################################################
-# Common definitions to compile all sources
+# Common definitions to compile all sources (app code and third party)
-
-# Do not use MMX optimizations in PNG code
-add_definitions(-DPNG_NO_MMX_CODE)
 
 # Debug C/C++ flags
 if(CMAKE_BUILD_TYPE STREQUAL Debug)
@@ -150,6 +139,25 @@ if(NOT USE_SHARED_CURL)
   set(CURL_STATICLIB ON BOOL)
 endif()
 
+if(NOT USE_SHARED_ZLIB)
+  # Zlib generated zconf.h file
+  include_directories(${CMAKE_BINARY_DIR}/third_party/zlib)
+endif()
+
+if(USE_SHARED_LIBPNG)
+  find_package(PNG)
+  if(NOT PNG_FOUND)
+    message(FATAL_ERROR "libpng not found")
+  endif()
+  add_definitions(${PNG_DEFINITIONS})
+  include_directories(${PNG_INCLUDE_DIR})
+else()
+  include_directories(${LIBPNG_DIR})
+endif()
+
+# Do not use MMX optimizations in PNG code
+add_definitions(-DPNG_NO_MMX_CODE)
+
 ######################################################################
 # Allegro 4 backend
 

src/CMakeLists.txt

@@ -86,12 +86,7 @@ else()
 endif()
 
 if(USE_SHARED_LIBPNG)
-  find_package(PNG)
+  set(libs3rdparty ${libs3rdparty} ${PNG_LIBRARIES})
-  if(PNG_FOUND)
-    set(libs3rdparty ${libs3rdparty} ${PNG_LIBRARIES})
-    add_definitions(${PNG_DEFINITIONS})
-    include_directories(${PNG_INCLUDE_DIR})
-  endif(PNG_FOUND)
 else()
   set(libs3rdparty ${libs3rdparty} libpng)
 endif()