Add missing libelf.m4

build/autotools/includes/libelf.m4

@@ -0,0 +1,31 @@
+AC_DEFUN([CHECK_LIBELF],
+[
+  LIBELF_DIR="\$(top_srcdir)/lib/libelf/lib"
+  LIBELF_LIB="${LIBELF_DIR}/libelf.a"
+  LIBELF_BUNDLED="${LIBELF_LIB}"
+  LIBELF_INCLUDE="-I${LIBELF_DIR}"
+
+  AC_CHECK_HEADERS([gelf.h libelf.h], [
+    AC_CHECK_TYPES([Elf_Note], [
+      AC_DEFINE(HAVE_GELF_H, 1, [Define to 1 if you have the <gelf.h> header file.])
+      AC_CHECK_LIB(elf, gelf_getehdr, [
+        AC_DEFINE(HAVE_LIBELF, 1, [Define to 1 if you have the 'elf' library (-lelf).])
+        LIBELF_LIB="-Wl,-Bstatic -lelf -Wl,-Bdynamic"
+        LIBELF_BUNDLED=
+        LIBELF_INCLUDE=
+      ]) dnl AC_CHECK_LIB
+    ], dnl AC_CHECK_TYPES
+    [],
+    AC_LANG_SOURCE(
+      [[
+#include "gelf.h"
+#include "libelf.h"
+      ]])
+    )
+  ])
+
+  CPPFLAGS="${CPPFLAGS} ${LIBELF_INCLUDE}"
+
+  AC_SUBST([LIBELF_BUNDLED])
+  AC_SUBST([LIBELF_LIB])
+])