Building static libraries only applies to IL and not to ILU nor ILUT

[GabrieleGiuseppini]

Specifying BUILD_SHARED_LIBS only makes the IL library static, it has no effect on ILU nor ILUT.

Fix is quite simple, e.g. in the ILU CMakeLists.txt:

diff --git a/DevIL/src-ILU/CMakeLists.txt b/DevIL/src-ILU/CMakeLists.txt
index 17a3afe7..5816dada 100644
--- a/DevIL/src-ILU/CMakeLists.txt
+++ b/DevIL/src-ILU/CMakeLists.txt
@@ -42,9 +42,12 @@ source_group("Source Files" FILES src/*.cpp)
 source_group("Header Files" FILES ${ILU_INC} )
 source_group("Resource Files" FILES ${ILU_RSRC} )

-# Remove SHARED to create a static library
-add_library(ILU SHARED ${ILU_SRCS} ${ILU_INC} ${ILU_RSRC})
-
+if(BUILD_SHARED_LIBS)
+    add_library(ILU SHARED ${ILU_SRCS} ${ILU_INC} ${ILU_RSRC})
+    set_target_properties(ILU PROPERTIES SOVERSION 1)
+else(BUILD_SHARED_LIBS)
+    add_library(ILU ${ILU_SRCS} ${ILU_INC} ${ILU_RSRC})
+endif(BUILD_SHARED_LIBS)