Adds ssdeep support in our build system

ssdeep will be used with the @fuzzyHash operator which is under
development

build/find_ssdeep.m4

@@ -0,0 +1,84 @@
+dnl Check for SSDEEP Libraries
+dnl CHECK_SSDEEP(ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND])
+dnl Sets:
+dnl  SSDEEP_CFLAGS
+dnl  SSDEEP_LDFLAGS
+
+AC_DEFUN([CHECK_SSDEEP],
+[dnl
+
+SSDEEP_CFLAGS=""
+SSDEEP_LDFLAGS=""
+SSDEEP_LDADD=""
+
+AC_ARG_WITH(
+    ssdeep,
+    [AC_HELP_STRING([--with-ssdeep=PATH],[Path to ssdeep prefix])]
+    ,, with_ssdeep=yes)
+
+AS_CASE(["${with_ssdeep}"],
+    [no], [test_paths=],
+    [yes], [test_paths="/usr/lib /usr/local/lib /usr/local/libfuzzy /usr/local/fuzzy /usr/local /opt/libfuzzy /opt/fuzzy /opt /usr"])
+    [test_paths="${with_ssdeep}"],
+
+AS_IF([test "x${test_paths}" != "x"], [
+AC_MSG_CHECKING([for ssdeep path])
+  
+  SSDEEP_LIB_NAME="fuzzy"
+  SSDEEP_LIB_FILENAME="lib$SSDEEP_LIB_NAME.so"
+
+  if test -z "$withssdeep" -o "$withssdeep" = "yes"; then
+    for i in ${test_paths}; do
+      if test -f "$i/$SSDEEP_LIB_FILENAME"; then
+        SSDEEP_LIB_DIR="$i"
+      fi
+    done
+  else
+    if test -f "$withssdeep/$SSDEEP_LIB_FILENAME"; then
+      SSDEEP_LIB_DIR="$withssdeep"
+    else
+      if test -f "$withssdeep/.libs/$SSDEEP_LIB_FILENAME"; then
+        SSDEEP_LIB_DIR="$withssdeep/.libs/"
+      fi
+    fi
+  fi
+
+  SSDEEP_LDFLAGS="-l$SSDEEP_LIB_NAME"
+  SSDEEP_LDADD="-l$SSDEEP_LIB_NAME"
+
+  if test -z "$withssdeep" -o "$withssdeep" = "yes"; then
+    for i in /usr/include /usr/local/include; do
+      if test -f "$i/$SSDEEP_LIB_NAME.h"; then
+        SSDEEP_CFLAGS="-I$i"
+      fi
+    done
+  else
+    if test -f "$withssdeep/../$SSDEEP_LIB_NAME.h"; then
+      SSDEEP_CFLAGS="-I$withssdeep/../"
+    else
+      if test -f "$withssdeep/$SSDEEP_LIB_NAME.h"; then
+        SSDEEP_CFLAGS="-I$withssdeep"
+      fi
+    fi
+  fi
+
+])  
+ 
+    if test -z "${SSDEEP_CFLAGS}"; then
+        AC_MSG_RESULT([no])
+	SSDEEP_LDFLAGS=""
+	SSDEEP_LDADD=""
+	#ifelse([$2], , AC_MSG_NOTICE([optional ssdeep library not found]), $2)
+    else
+      SSDEEP_CFLAGS="-DWITH_SSDEEP ${SSDEEP_CFLAGS}"
+        AC_MSG_RESULT([${SSDEEP_LDFLAGS} ${SSDEEP_CFLAGS}]) 
+#AC_MSG_NOTICE([using ssdeep: ${SSDEEP_CFLAGS} ${SSDEEP_LDFLAGS}])
+#ifelse([$1], , , $1) 
+    fi 
+
+AC_SUBST(SSDEEP_LDFLAGS)
+AC_SUBST(SSDEEP_LDADD)
+AC_SUBST(SSDEEP_CFLAGS)
+
+
+])