Revert "[cleanup] Remove enable trick for UMFPack" and GMP

These commits broke compiling / linking if one package was found
but the includes / libraries were not added. We need a different
approach to hide the ENABLE_* trick from the user and keep full
testing capabilities.
This reverts commits 0f12caff
and d75c3a46.

cmake/modules/AddGMPFlags.cmake

@@ -5,6 +5,9 @@ function(add_dune_gmp_flags _targets)
   if(GMP_FOUND)
     foreach(_target ${_targets})
       target_link_libraries(${_target} ${GMP_LIBRARIES})
+      set_property(TARGET ${_target}
+        APPEND_STRING
+        PROPERTY COMPILE_FLAGS "-DENABLE_GMP=1 ")
       foreach(_path ${GMP_INCLUDE_DIRS})
         set_property(TARGET ${_target}
           APPEND_STRING

cmake/modules/AddUMFPackFlags.cmake

-# module providing convenience methods for compiling
-# binaries with UMFPack support
+# module providing convenience mehtods for compiling bianries with UMFPack support
 #
 # Provides the following functions:
 #
@@ -13,7 +12,7 @@ function(add_dune_umfpack_flags _targets)
       get_target_property(_props ${_target} COMPILE_FLAGS)
       string(REPLACE "_props-NOTFOUND" "" _props "${_props}")
       set_target_properties(${_target} PROPERTIES COMPILE_FLAGS
-        "${_props} ${UMFPACK_DUNE_COMPILE_FLAGS}")
+        "${_props} ${UMFPACK_DUNE_COMPILE_FLAGS} -DENABLE_UMFPACK")
     endforeach(_target ${_targets})
   endif(UMFPACK_FOUND)
-endfunction(add_dune_umfpack_flags)
+endfunction(add_dune_umfpack_flags)
\ No newline at end of file

cmake/modules/FindGMP.cmake

@@ -64,6 +64,7 @@ mark_as_advanced(GMP_LIB GMPXX_LIB GMP_INCLUDE_DIR)
 if(GMP_FOUND)
   set(GMP_INCLUDE_DIRS ${GMP_INCLUDE_DIR})
   set(GMP_LIBRARIES ${GMP_LIB} ${GMPXX_LIB})
+  set(GMP_COMPILE_FLAGS "-DENABLE_GMP=1")
   # log result
   file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
     "Determing location of GMP succeded:\n"
@@ -83,6 +84,7 @@ set(HAVE_GMP ${GMP_FOUND})
 
 # register all GMP related flags
 if(HAVE_GMP)
-  dune_register_package_flags(LIBRARIES "${GMP_LIB};${GMPXX_LIB}"
+  dune_register_package_flags(COMPILE_DEFINITIONS "ENABLE_GMP=1"
+                              LIBRARIES "${GMP_LIB};${GMPXX_LIB}"
                               INCLUDE_DIRS "${GMP_INCLUDE_DIR}")
 endif()

cmake/modules/FindUMFPack.cmake

@@ -96,7 +96,7 @@ set(HAVE_UMFPACK ${UMFPACK_FOUND})
 
 # register all umfpack related flags
 if(UMFPACK_FOUND)
-  dune_register_package_flags(
-    LIBRARIES "${UMFPACK_LIBRARIES}"
-    INCLUDE_DIRS "${UMFPACK_INCLUDE_DIRS}")
+  dune_register_package_flags(COMPILE_DEFINITIONS "ENABLE_UMFPACK=1"
+                            LIBRARIES "${UMFPACK_LIBRARIES}"
+                            INCLUDE_DIRS "${UMFPACK_INCLUDE_DIRS}")
 endif()

config.h.cmake

@@ -43,8 +43,9 @@
    deprecated MPI_CPPFLAGS) */
 #cmakedefine HAVE_MPI ENABLE_MPI
 
-/* Define to 1 if you have the GNU GMP library. */
-#cmakedefine HAVE_GMP 1
+/* Define if you have the GNU GMP library. The value should be ENABLE_GMP
+   to facilitate activating and deactivating GMP using compile flags. */
+#cmakedefine HAVE_GMP ENABLE_GMP
 
 /* Define to 1 if you have the symbol mprotect. */
 #cmakedefine HAVE_MPROTECT 1
@@ -107,8 +108,8 @@
 /* does the compiler support the keyword 'final'? */
 #cmakedefine HAVE_KEYWORD_FINAL 1
 
-/* Define to 1 if the UMFPack library is available */
-#cmakedefine HAVE_UMFPACK 1
+/* Define to if the UMFPack library is available */
+#cmakedefine HAVE_UMFPACK ENABLE_UMFPACK
 
 /* Define to ENABLE_PARMETIS if you have the Parmetis library.
    This is only true if MPI was found

dune/common/promotiontraits.hh

@@ -28,7 +28,7 @@ namespace Dune {
 
   // Specialization for the case of two equal types
   // One should think that the generic template should handle this case as well.
-  // However, the fvectortest.cc unit test fails without it if gmp is used.
+  // However, the fvectortest.cc unit test fails without it if ENABLE_GMP is set.
   template <typename T1>
   struct PromotionTraits<T1,T1> { typedef T1 PromotedType; };