check if -lrt is needed for clock_gettime

Makefile.in

@@ -10,6 +10,7 @@ GO     = @GO@
 GOFMT  = @GOFMT@
 GOROOT = @GOROOT@
 AUTORECONF = @AUTORECONF@
+LRT_LDFLAG = @LRT_LDFLAG@
 # or 386, arm
 arch   = amd64
 CGO_ENABLED = 1
@@ -128,7 +129,7 @@ ifeq ($(rocksdb),yes)
 GO_BUILD_TAGS += rocksdb
 storage_engines += $(rocksdb_deps)
 CGO_CFLAGS +=  -I$(rocksdb_dir)/include
-CGO_LDFLAGS += -L$(rocksdb_dir) -lrocksdb
+CGO_LDFLAGS += -L$(rocksdb_dir) -lrocksdb $(LRT_LDFLAG)
 endif
 CGO_CFLAGS  += -I$(leveldb_dir)/include -I$(hyperleveldb_dir)/include
 CGO_LDFLAGS += -L$(leveldb_dir) -L$(hyperleveldb_dir)/.libs -L$(snappy_dir)/.libs -lleveldb -lhyperleveldb -lsnappy
@@ -181,7 +182,7 @@ ifeq ($(uname_S),Linux)
 	bash -c "cd $(rocksdb_dir); \
 	wget -O $(rocksdb_file) https://github.com/facebook/rocksdb/archive/$(rocksdb_file); \
 	tar --strip-components=1 -xvzf $(rocksdb_file); \
-	CFLAGS='-I$(snappy_dir) $(cflags)' CXXFLAGS='-I$(snappy_dir) $(cflags)' LDFLAGS='-L$(snappy_dir)/.libs' $(MAKE) librocksdb.a"
+	CFLAGS='-I$(snappy_dir) $(cflags)' CXXFLAGS='-I$(snappy_dir) $(cflags)' LDFLAGS='-L$(snappy_dir)/.libs $(LRT_LDFLAG)' $(MAKE) librocksdb.a"
 endif
 
 $(hyperleveldb_deps): $(snappy_deps)

configure

@@ -593,6 +593,7 @@ CPPFLAGS
 LDFLAGS
 CFLAGS
 CC
+LRT_LDFLAG
 with_flex
 with_bison
 AUTORECONF
@@ -1797,6 +1798,7 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
 
+
 # Extract the first word of "protoc", so it can be a program name with args.
 set dummy protoc; ac_word=$2
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
@@ -2927,6 +2929,68 @@ else
   as_fn_error $? "\"cannot find libbz2\"" "$LINENO" 5
 fi
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing clock_gettime" >&5
+$as_echo_n "checking for library containing clock_gettime... " >&6; }
+if ${ac_cv_search_clock_gettime+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_func_search_save_LIBS=$LIBS
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char clock_gettime ();
+int
+main ()
+{
+return clock_gettime ();
+  ;
+  return 0;
+}
+_ACEOF
+for ac_lib in '' rt; do
+  if test -z "$ac_lib"; then
+    ac_res="none required"
+  else
+    ac_res=-l$ac_lib
+    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
+  fi
+  if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_search_clock_gettime=$ac_res
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext
+  if ${ac_cv_search_clock_gettime+:} false; then :
+  break
+fi
+done
+if ${ac_cv_search_clock_gettime+:} false; then :
+
+else
+  ac_cv_search_clock_gettime=no
+fi
+rm conftest.$ac_ext
+LIBS=$ac_func_search_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_search_clock_gettime" >&5
+$as_echo "$ac_cv_search_clock_gettime" >&6; }
+ac_res=$ac_cv_search_clock_gettime
+if test "$ac_res" != no; then :
+  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
+
+else
+  as_fn_error $? "\"Cannot find an implementation of clock_gettime\"" "$LINENO" 5
+fi
+
+
+if test x"${ac_cv_search_clock_gettime}" != x"none required"; then
+   LRT_LDFLAG=${ac_cv_search_clock_gettime}
+fi
 
 if test x"${with_bison}" == x""; then
    # Extract the first word of "bison", so it can be a program name with args.

configure.ac

@@ -6,6 +6,7 @@ AC_SUBST(GOROOT)
 AC_SUBST(AUTORECONF)
 AC_SUBST(with_bison)
 AC_SUBST(with_flex)
+AC_SUBST(LRT_LDFLAG)
 AC_PATH_PROG(PROTOC, protoc, "notfound")
 if test x"${PROTOC}" == x"notfound"; then
     AC_MSG_ERROR([Please install protobuf before trying to build Influxdb])
@@ -47,6 +48,11 @@ if test x"${AUTORECONF}" == x"notfound"; then
 fi
 AC_CHECK_LIB(z, gzdopen,,AC_MSG_ERROR("cannot find libz"))
 AC_CHECK_LIB(bz2, BZ2_bzReadOpen,,AC_MSG_ERROR("cannot find libbz2"))
+AC_SEARCH_LIBS(clock_gettime,rt,,AC_MSG_ERROR("Cannot find an implementation of clock_gettime"))
+
+if test x"${ac_cv_search_clock_gettime}" != x"none required"; then
+   LRT_LDFLAG=${ac_cv_search_clock_gettime}
+fi
 
 if test x"${with_bison}" == x""; then
    AC_PATH_PROG(with_bison, bison, "notfound")