build system: improved handling of silent mode

The top-level makefile attempted to detect if make was being run
in silent mode (-s option).  It then turned off reporting of
commands as they were run.  There were false positives where
unrelated 's' characters in the command line were detected as
silent mode.

Import the relevant section from the latest Linux build system to
improve matters.

1 files changed, 8 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index 51f460583..9dd359244 100644
--- a/Makefile
+++ b/Makefile
@@ -286,8 +286,15 @@ endif
 
 # If the user is running make -s (silent mode), suppress echoing of
 # commands
+# make-4.0 (and later) keep single letter options in the 1st word of MAKEFLAGS.
 
-ifneq ($(findstring s,$(MAKEFLAGS)),)
+ifeq ($(filter 3.%,$(MAKE_VERSION)),)
+short-opts := $(firstword -$(MAKEFLAGS))
+else
+short-opts := $(filter-out --%,$(MAKEFLAGS))
+endif
+
+ifneq ($(findstring s,$(short-opts)),)
   quiet=silent_
 endif