For building perf without libelf, we can set NO_LIBELF=1 as a argument
of make.  It then defines NO_LIBELF_SUPPORT macro for C code to do the
proper handling.  However it usually used in a negative semantics -
e.g. #ifndef - so we saw double negations which can be misleading.
Convert it to a positive form to make it more readable.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1348824728-14025-4-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 endif
 
 ifdef NO_LIBELF
-BASIC_CFLAGS += -DNO_LIBELF_SUPPORT
-
 EXTLIBS := $(filter-out -lelf,$(EXTLIBS))
 
 # Remove ELF/DWARF dependent codes
 LIB_OBJS += $(OUTPUT)util/symbol-minimal.o
 
 else # NO_LIBELF
+BASIC_CFLAGS += -DLIBELF_SUPPORT
 
-ifneq ($(call try-cc,$(SOURCE_ELF_MMAP),$(FLAGS_COMMON)),y)
-       BASIC_CFLAGS += -DLIBELF_NO_MMAP
+ifeq ($(call try-cc,$(SOURCE_ELF_MMAP),$(FLAGS_COMMON)),y)
+       BASIC_CFLAGS += -DLIBELF_MMAP
 endif
 
 ifndef NO_DWARF
 
                                 * account this as unresolved.
                                 */
                        } else {
-#ifndef NO_LIBELF_SUPPORT
+#ifdef LIBELF_SUPPORT
                                pr_warning("no symbols found in %s, maybe "
                                           "install a debug package?\n",
                                           al.map->dso->long_name);
 
        { "version",    cmd_version,    0 },
        { "script",     cmd_script,     0 },
        { "sched",      cmd_sched,      0 },
-#ifndef NO_LIBELF_SUPPORT
+#ifdef LIBELF_SUPPORT
        { "probe",      cmd_probe,      0 },
 #endif
        { "kmem",       cmd_kmem,       0 },
 
      }' "Documentation/perf-$cmd.txt"
 done
 
-echo "#ifndef NO_LIBELF_SUPPORT"
+echo "#ifdef LIBELF_SUPPORT"
 sed -n -e 's/^perf-\([^        ]*\)[   ].* full.*/\1/p' command-list.txt |
 sort |
 while read cmd
            p
      }' "Documentation/perf-$cmd.txt"
 done
-echo "#endif /* NO_LIBELF_SUPPORT */"
+echo "#endif /* LIBELF_SUPPORT */"
 echo "};"
 
                pr_warning(", continuing without symbols\n");
                return -1;
        } else if (nr == 0) {
-#ifndef NO_LIBELF_SUPPORT
+#ifdef LIBELF_SUPPORT
                const size_t len = strlen(name);
                const size_t real_len = len - sizeof(DSO__DELETED);
 
 
 #include <byteswap.h>
 #include <libgen.h>
 
-#ifndef NO_LIBELF_SUPPORT
+#ifdef LIBELF_SUPPORT
 #include <libelf.h>
 #include <gelf.h>
 #include <elf.h>
  * libelf 0.8.x and earlier do not support ELF_C_READ_MMAP;
  * for newer versions we can use mmap to reduce memory usage:
  */
-#ifdef LIBELF_NO_MMAP
-# define PERF_ELF_C_READ_MMAP ELF_C_READ
-#else
+#ifdef LIBELF_MMAP
 # define PERF_ELF_C_READ_MMAP ELF_C_READ_MMAP
+#else
+# define PERF_ELF_C_READ_MMAP ELF_C_READ
 #endif
 
 #ifndef DMGL_PARAMS
        int fd;
        enum dso_binary_type type;
 
-#ifndef NO_LIBELF_SUPPORT
+#ifdef LIBELF_SUPPORT
        Elf *elf;
        GElf_Ehdr ehdr;