Merge branch 'ab/gnumake-4.4-fix'

Adjust our Makefiles for GNUmake 4.4

* ab/gnumake-4.4-fix:
  Makefiles: change search through $(MAKEFLAGS) for GNU make 4.4

git-gui/Makefile

@@ -116,7 +116,7 @@ ifeq ($(uname_S),Darwin)
 	TKEXECUTABLE = $(shell basename "$(TKFRAMEWORK)" .app)
 endif
 
-ifeq ($(findstring $(MAKEFLAGS),s),s)
+ifeq ($(findstring $(firstword -$(MAKEFLAGS)),s),s)
 QUIET_GEN =
 endif
 

shared.mak

@@ -37,13 +37,13 @@ space := $(empty) $(empty)
 QUIET_SUBDIR0  = +$(MAKE) -C # space to separate -C and subdir
 QUIET_SUBDIR1  =
 
-ifneq ($(findstring w,$(MAKEFLAGS)),w)
+ifneq ($(findstring w,$(firstword -$(MAKEFLAGS))),w)
 PRINT_DIR = --no-print-directory
 else # "make -w"
 NO_SUBDIR = :
 endif
 
-ifneq ($(findstring s,$(MAKEFLAGS)),s)
+ifneq ($(findstring s,$(firstword -$(MAKEFLAGS))),s)
 ifndef V
 ## common
 	QUIET_SUBDIR0  = +@subdir=