[CMake] Don't search for malloc.h, stdint.h and memory.

We assume anyway that stdint.h and memrory are provided. The
according macros are never used. They were probably provided
to stay as compatible to Autotools as possible.
This fixes FS#1605.

cmake/modules/DuneMacros.cmake

@@ -597,14 +597,6 @@ macro(dune_project)
 
   include(DuneCxaDemangle)
 
-  # search for headers
-  include(CheckIncludeFile)
-  include(CheckIncludeFileCXX)
-  check_include_file("malloc.h" HAVE_MALLOC_H)
-  check_include_file("stdint.h" HAVE_STDINT_H)
-  check_include_file_cxx("memory" HAVE_MEMORY)
-  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -DHAVE_MEMORY=${HAVE_MEMORY}")
-
   # set include path and link path for the current project.
   include_directories("${CMAKE_BINARY_DIR}")
   include_directories("${CMAKE_SOURCE_DIR}")

cmake/modules/FindMProtect.cmake

@@ -4,6 +4,7 @@
 # Sets the following variables
 # HAVE_SYS_MMAN_H
 # HAVE_MPROTECT
+include(CheckIncludeFile)
 check_include_file("sys/mman.h" HAVE_SYS_MMAN_H)
 include(CheckCSourceCompiles)
 check_c_source_compiles("