pkg-utils: mask tput failure for non-interactive sessions

When invoking a build from a non-interactive session (for example, a
Jenkins build), there is no terminal session to modify. When preparing
variables to track the bold and boldoff mode sequences, the `tput`
command will always fail as there is no terminal to query. The following
change masks the error message when `tput` fails; leaving the TERM_BOLD
and TERM_RESET variables empty.

Signed-off-by: James Knight <james.d.knight@live.com>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/pkg-utils.mk

@@ -84,8 +84,8 @@ suitable-extractor = $(INFLATE$(suffix $(1)))
 
 # MESSAGE Macro -- display a message in bold type
 MESSAGE = echo "$(TERM_BOLD)>>> $($(PKG)_NAME) $($(PKG)_VERSION) $(call qstrip,$(1))$(TERM_RESET)"
-TERM_BOLD := $(shell tput smso)
-TERM_RESET := $(shell tput rmso)
+TERM_BOLD := $(shell tput smso 2>/dev/null)
+TERM_RESET := $(shell tput rmso 2>/dev/null)
 
 # Utility functions for 'find'
 # findfileclauses(filelist) => -name 'X' -o -name 'Y'