Adds support to libmemcached into the build system

Libmemcached will be further used to handle centralized collections.

build/find_libmemcache.m4

@@ -0,0 +1,82 @@
+dnl Check for LIBMEMCACHED Libraries
+dnl CHECK_LIBMEMCACHED(ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND])
+dnl Sets:
+dnl  LIBMEMCACHED_CFLAGS
+dnl  LIBMEMCACHED_LDFLAGS
+dnl  LIBMEMCACHED_LDADD
+
+AC_DEFUN([CHECK_LIBMEMCACHED],
+[dnl
+
+LIBMEMCACHED_CFLAGS=""
+LIBMEMCACHED_LDFLAGS=""
+LIBMEMCACHED_LDADD=""
+
+AC_ARG_WITH(
+    libmemcached,
+    [AC_HELP_STRING([--with-libmemcached=PATH],[Path to libmemcached prefix])]
+    ,, with_libmemcached=yes)
+
+AS_CASE(["${with_libmemcached}"],
+    [no], [test_paths=],
+    [yes], [test_paths="/usr/lib /usr/local/lib /usr/local/libmemcached /usr/local/libmemcached /usr/local /opt/libmemcached /opt/libmemcached /opt /usr /usr/lib/x86_64-linux-gnu/"],
+    [test_paths="${with_libmemcached}"])
+
+AS_IF([test "x${test_paths}" != "x"], [
+AC_MSG_CHECKING([for libmemcached path])
+  
+  LIBMEMCACHED_LIB_NAME="memcached"
+  LIBMEMCACHED_LIB_FILENAME="lib$LIBMEMCACHED_LIB_NAME.so"
+
+  if test -z "$withlibmemcached" -o "$withlibmemcached" = "yes"; then
+    for i in ${test_paths}; do
+      if test -f "$i/$LIBMEMCACHED_LIB_FILENAME"; then
+        LIBMEMCACHED_LIB_DIR="$i"
+      fi
+    done
+  else
+    if test -f "$withlibmemcached/$LIBMEMCACHED_LIB_FILENAME"; then
+      LIBMEMCACHED_LIB_DIR="$withlibmemcached"
+    else
+      if test -f "$withlibmemcached/.libs/$LIBMEMCACHED_LIB_FILENAME"; then
+        LIBMEMCACHED_LIB_DIR="$withlibmemcached/.libs/"
+      fi
+    fi
+  fi
+
+  LIBMEMCACHED_LDFLAGS="-l$LIBMEMCACHED_LIB_NAME"
+  LIBMEMCACHED_LDADD="-l$LIBMEMCACHED_LIB_NAME"
+
+  if test -z "$withlibmemcached" -o "$withlibmemcached" = "yes"; then
+    for i in /usr/include /usr/local/include /usr/include/libmemcached; do
+      if test -f "$i/$LIBMEMCACHED_LIB_NAME.h"; then
+        LIBMEMCACHED_CFLAGS="-I$i"
+      fi
+    done
+  else
+    if test -f "$withlibmemcached/../$LIBMEMCACHED_LIB_NAME.h"; then
+      LIBMEMCACHED_CFLAGS="-I$withlibmemcached/../"
+    else
+      if test -f "$withlibmemcached/$LIBMEMCACHED_LIB_NAME.h"; then
+        LIBMEMCACHED_CFLAGS="-I$withlibmemcached"
+      fi
+    fi
+  fi
+
+])  
+ 
+    if test -z "${LIBMEMCACHED_CFLAGS}"; then
+        AC_MSG_NOTICE([optional libmemcached library not found])
+	LIBMEMCACHED_LDFLAGS=""
+        LIBMEMCACHED_LDADD=""
+        AC_MSG_RESULT([no])
+    else
+        LIBMEMCACHED_CFLAGS="-DWITH_LIBMEMCACHED ${LIBMEMCACHED_CFLAGS}"
+        AC_SUBST(LIBMEMCACHED_LDFLAGS)
+        AC_SUBST(LIBMEMCACHED_LDADD)
+        AC_SUBST(LIBMEMCACHED_CFLAGS)
+
+        AC_MSG_RESULT([${LIBMEMCACHED_LDFLAGS} ${LIBMEMCACHED_CFLAGS}]) 
+    fi 
+
+])