updated cmakelists.

contrib/zlib/CMakeLists.txt

@@ -130,6 +130,12 @@ set(ZLIB_SRCS
     zutil.c
 )
 
+if(NOT MINGW)
+    set(ZLIB_DLL_SRCS
+        win32/zlib1.rc # If present will override custom build rule below.
+    )
+endif()
+
 if(CMAKE_COMPILER_IS_GNUCC)
     if(ASM686)
         set(ZLIB_ASMS contrib/asm686/match.S)
@@ -168,7 +174,26 @@ file(READ ${CMAKE_CURRENT_SOURCE_DIR}/zlib.h _zlib_h_contents)
 string(REGEX REPLACE ".*#define[ \t]+ZLIB_VERSION[ \t]+\"([-0-9A-Za-z.]+)\".*"
     "\\1" ZLIB_FULL_VERSION ${_zlib_h_contents})
 
+if(MINGW)
+    # This gets us DLL resource information when compiling on MinGW.
+    if(NOT CMAKE_RC_COMPILER)
+        set(CMAKE_RC_COMPILER windres.exe)
+    endif()
+
+    add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/zlib1rc.obj
+                       COMMAND ${CMAKE_RC_COMPILER}
+                            -D GCC_WINDRES
+                            -I ${CMAKE_CURRENT_SOURCE_DIR}
+                            -I ${CMAKE_CURRENT_BINARY_DIR}
+                            -o ${CMAKE_CURRENT_BINARY_DIR}/zlib1rc.obj
+                            -i ${CMAKE_CURRENT_SOURCE_DIR}/win32/zlib1.rc)
+    set(ZLIB_DLL_SRCS ${CMAKE_CURRENT_BINARY_DIR}/zlib1rc.obj)
+endif(MINGW)
+
+add_library(zlib SHARED ${ZLIB_SRCS} ${ZLIB_ASMS} ${ZLIB_DLL_SRCS} ${ZLIB_PUBLIC_HDRS} ${ZLIB_PRIVATE_HDRS})
 add_library(zlibstatic STATIC ${ZLIB_SRCS} ${ZLIB_ASMS} ${ZLIB_PUBLIC_HDRS} ${ZLIB_PRIVATE_HDRS})
+set_target_properties(zlib PROPERTIES DEFINE_SYMBOL ZLIB_DLL)
+set_target_properties(zlib PROPERTIES SOVERSION 1)
 
 INSTALL( TARGETS zlibstatic
          LIBRARY DESTINATION ${ASSIMP_LIB_INSTALL_DIR}