make: replace curly braces with parenthesis

Makefile

@@ -20,11 +20,11 @@ docclean:
 
 clean:
 	@echo "Cleaning all build products for the current board"
-	@find ./examples/ ./tests/ -maxdepth 2 -mindepth 2 -type f -name Makefile -execdir "${MAKE}" clean ';'
+	@find ./examples/ ./tests/ -maxdepth 2 -mindepth 2 -type f -name Makefile -execdir "$(MAKE)" clean ';'
 
 distclean: docclean
 	@echo "Cleaning all build products"
-	@find ./examples/ ./tests/ -maxdepth 2 -mindepth 2 -type f -name Makefile -execdir "${MAKE}" distclean ';'
+	@find ./examples/ ./tests/ -maxdepth 2 -mindepth 2 -type f -name Makefile -execdir "$(MAKE)" distclean ';'
 
 welcome:
 	@echo "Welcome to RIOT - The friendly OS for IoT!"

Makefile.base

@@ -3,24 +3,24 @@ ifeq (, $(__RIOTBUILD_FLAG))
 endif
 
 unexport DIRS
-DIRS := $(sort $(abspath ${DIRS}))
+DIRS := $(sort $(abspath $(DIRS)))
 
 MODULE ?= $(shell basename $(CURDIR))
 
-.PHONY: all ${DIRS:%=ALL--%} ${DIRS:%=CLEAN--%}
+.PHONY: all $(DIRS:%=ALL--%) $(DIRS:%=CLEAN--%)
 
 all: $(BINDIR)/$(MODULE).a ..nothing
 
 ..nothing:
 	@:
 
-clean:: ${DIRS:%=CLEAN--%}
+clean:: $(DIRS:%=CLEAN--%)
 
-${DIRS:%=ALL--%}:
+$(DIRS:%=ALL--%):
-	$(QQ)"$(MAKE)" -C ${@:ALL--%=%}
+	$(QQ)"$(MAKE)" -C $(@:ALL--%=%)
 
-${DIRS:%=CLEAN--%}:
+$(DIRS:%=CLEAN--%):
-	$(QQ)"$(MAKE)" -C ${@:CLEAN--%=%} clean
+	$(QQ)"$(MAKE)" -C $(@:CLEAN--%=%) clean
 
 ## submodules
 ifeq (1, $(SUBMODULES))
@@ -67,7 +67,7 @@ $(BINDIR)/$(MODULE)/:
 
 $(BINDIR)/$(MODULE).a $(OBJ): | $(BINDIR)/$(MODULE)/
 
-$(BINDIR)/$(MODULE).a: $(OBJ) | ${DIRS:%=ALL--%}
+$(BINDIR)/$(MODULE).a: $(OBJ) | $(DIRS:%=ALL--%)
 	@# Recreate archive to cleanup deleted/non selected source files objects
 	$(Q)$(RM) $@
 	$(Q)$(AR) $(ARFLAGS) $@ $^

Makefile.include

@@ -49,17 +49,17 @@ override PKGDIRBASE     := $(abspath $(PKGDIRBASE))
 override DLCACHE_DIR    := $(abspath $(DLCACHE_DIR))
 
 # Ensure that all directories are set and don't contain spaces.
-ifneq (, $(filter-out 1, $(foreach v,${__DIRECTORY_VARIABLES},$(words ${${v}}))))
+ifneq (, $(filter-out 1, $(foreach v,$(__DIRECTORY_VARIABLES),$(words $($(v))))))
   $(info Aborting compilation for your safety.)
-  $(info Related variables = ${__DIRECTORY_VARIABLES})
+  $(info Related variables = $(__DIRECTORY_VARIABLES))
   $(error Make sure no path override is empty or contains spaces!)
 endif
 
 # Use absolute paths in recusive "make" even if overriden on command line.
-MAKEOVERRIDES += $(foreach v,${__DIRECTORY_VARIABLES},${v}=${${v}})
+MAKEOVERRIDES += $(foreach v,$(__DIRECTORY_VARIABLES),$(v)=$($(v)))
 
 # Path to the current directory relative to RIOTPROJECT
-BUILDRELPATH ?= ${PWD:${RIOTPROJECT}/%=%}/
+BUILDRELPATH ?= $(PWD:$(RIOTPROJECT)/%=%)/
 
 # get host operating system
 OS := $(shell uname)
@@ -136,7 +136,7 @@ endif
 CFLAGS += -Wno-implicit-fallthrough
 CXXFLAGS += -Wno-implicit-fallthrough
 
-ifneq (10,$(if ${RIOT_VERSION},1,0)$(if ${__RIOTBUILD_FLAG},1,0))
+ifneq (10,$(if $(RIOT_VERSION),1,0)$(if $(__RIOTBUILD_FLAG),1,0))
 
 # Provide a shallow sanity check. You cannot call `make` in a module directory.
 export __RIOTBUILD_FLAG := RIOT
@@ -181,7 +181,7 @@ ifeq (,$(UNZIP_HERE))
   endif
 endif
 
-ifeq (, ${APPLICATION})
+ifeq (, $(APPLICATION))
     $(error An application name must be specified as APPLICATION.)
 endif
 ifneq (0,$(shell test -d $(RIOTBOARD)/$(BOARD); echo $$?))
@@ -324,7 +324,7 @@ ifeq ($(BUILD_IN_DOCKER),1)
 link: ..in-docker-container
 else
 ## make script for your application. Build RIOT-base here!
-link: ..compiler-check ..build-message $(RIOTBUILD_CONFIG_HEADER_C) $(USEPKG:%=${BINDIR}/%.a) $(APPDEPS)
+link: ..compiler-check ..build-message $(RIOTBUILD_CONFIG_HEADER_C) $(USEPKG:%=$(BINDIR)/%.a) $(APPDEPS)
 	$(Q)DIRS="$(DIRS)" "$(MAKE)" -C $(APPDIR) -f $(RIOTMAKE)/application.inc.mk
 ifeq (,$(RIOTNOLINK))
 ifeq ($(BUILDOSXNATIVE),1)
@@ -340,11 +340,11 @@ endif # BUILD_IN_DOCKER
 ..compiler-check:
 	@command -v $(CC) >/dev/null 2>&1 || \
 		{ $(COLOR_ECHO) \
-		'${COLOR_RED}Compiler $(CC) is required but not found in PATH.  Aborting.${COLOR_RESET}'; \
+		'$(COLOR_RED)Compiler $(CC) is required but not found in PATH.  Aborting.$(COLOR_RESET)'; \
 		exit 1; }
 
 ..build-message:
-	@$(COLOR_ECHO) '${COLOR_GREEN}Building application "$(APPLICATION)" for "$(BOARD)" with MCU "$(MCU)".${COLOR_RESET}'
+	@$(COLOR_ECHO) '$(COLOR_GREEN)Building application "$(APPLICATION)" for "$(BOARD)" with MCU "$(MCU)".$(COLOR_RESET)'
 	@$(COLOR_ECHO)
 
 # add extra include paths for packages in $(USEMODULE)
@@ -369,13 +369,13 @@ USEMODULE_INCLUDES_ = $(shell echo $(USEMODULE_INCLUDES) | tr ' ' '\n' | awk '!a
 
 INCLUDES += $(USEMODULE_INCLUDES_:%=-I%)
 
-.PHONY: pkg-prepare $(USEPKG:%=${BINDIR}/%.a)
+.PHONY: pkg-prepare $(USEPKG:%=$(BINDIR)/%.a)
 pkg-prepare:
 	-@for i in $(USEPKG) ; do "$(MAKE)" -C $(RIOTPKG)/$$i prepare ; done
 
-$(USEPKG:%=${BINDIR}/%.a): $(RIOTBUILD_CONFIG_HEADER_C) pkg-prepare
+$(USEPKG:%=$(BINDIR)/%.a): $(RIOTBUILD_CONFIG_HEADER_C) pkg-prepare
-	@mkdir -p ${BINDIR}
+	@mkdir -p $(BINDIR)
-	$(QQ)"$(MAKE)" -C $(RIOTPKG)/$(patsubst ${BINDIR}/%.a,%,$@)
+	$(QQ)"$(MAKE)" -C $(RIOTPKG)/$(patsubst $(BINDIR)/%.a,%,$@)
 
 clean:
 	-@for i in $(USEPKG) ; do "$(MAKE)" -C $(RIOTPKG)/$$i clean ; done
@@ -402,7 +402,7 @@ endif
 flash: $(BUILD_BEFORE_FLASH) $(FLASHDEPS)
 	@command -v $(FLASHER) >/dev/null 2>&1 || \
 		{ $(COLOR_ECHO) \
-		'${COLOR_RED}Flash program $(FLASHER) not found. Aborting.${COLOR_RESET}'; \
+		'$(COLOR_RED)Flash program $(FLASHER) not found. Aborting.$(COLOR_RESET)'; \
 		exit 1; }
 	$(FLASHER) $(FFLAGS)
 
@@ -414,7 +414,7 @@ preflash: $(BUILD_BEFORE_FLASH)
 term: $(filter flash, $(MAKECMDGOALS)) $(TERMDEPS)
 	@command -v $(TERMPROG) >/dev/null 2>&1 || \
 		{ $(COLOR_ECHO) \
-		'${COLOR_RED}Terminal program $(TERMPROG) not found. Aborting.${COLOR_RESET}'; \
+		'$(COLOR_RED)Terminal program $(TERMPROG) not found. Aborting.$(COLOR_RESET)'; \
 		exit 1; }
 	$(TERMPROG) $(TERMFLAGS)
 
@@ -427,28 +427,28 @@ doc:
 debug:
 	@command -v $(DEBUGGER) >/dev/null 2>&1 || \
 		{ $(COLOR_ECHO) \
-		'${COLOR_RED}Debug program $(DEBUGGER) not found. Aborting.${COLOR_RESET}'; \
+		'$(COLOR_RED)Debug program $(DEBUGGER) not found. Aborting.$(COLOR_RESET)'; \
 		exit 1; }
 	$(DEBUGGER) $(DEBUGGER_FLAGS)
 
 debug-server:
 	@command -v $(DEBUGSERVER) >/dev/null 2>&1 || \
 		{ $(COLOR_ECHO) \
-		'${COLOR_RED}Debug server program $(DEBUGSERVER) not found. Aborting.${COLOR_RESET}'; \
+		'$(COLOR_RED)Debug server program $(DEBUGSERVER) not found. Aborting.$(COLOR_RESET)'; \
 		exit 1; }
 	$(DEBUGSERVER) $(DEBUGSERVER_FLAGS)
 
 emulate:
 	@command -v $(EMULATOR) >/dev/null 2>&1 || \
 		{ $(COLOR_ECHO) \
-		'${COLOR_RED}Emulation program $(EMULATOR) not found. Aborting.${COLOR_RESET}'; \
+		'$(COLOR_RED)Emulation program $(EMULATOR) not found. Aborting.$(COLOR_RESET)'; \
 		exit 1; }
 	$(EMULATOR) $(EMULATOR_FLAGS)
 
 reset:
 	@command -v $(RESET) >/dev/null 2>&1 || \
 		{ $(COLOR_ECHO) \
-		'${COLOR_RED}Reset program $(RESET) not found. Aborting.${COLOR_RESET}'; \
+		'$(COLOR_RED)Reset program $(RESET) not found. Aborting.$(COLOR_RESET)'; \
 		exit 1; }
 	$(RESET) $(RESET_FLAGS)
 
@@ -458,7 +458,7 @@ OBJDUMPFLAGS ?= -S -D -h
 objdump:
 	@command -v $(OBJDUMP) >/dev/null 2>&1 || \
 		{ $(COLOR_ECHO) \
-		'${COLOR_RED}Objdump program $(OBJDUMP) not found. Aborting.${COLOR_RESET}'; \
+		'$(COLOR_RED)Objdump program $(OBJDUMP) not found. Aborting.$(COLOR_RESET)'; \
 		exit 1; }
 	$(OBJDUMP) $(OBJDUMPFLAGS) $(ELFFILE) | less
 
@@ -513,7 +513,7 @@ ifneq (, $(filter all, $(if $(MAKECMDGOALS), $(MAKECMDGOALS), all)))
   # If there is a whitelist, then test if the board is whitelisted.
   ifneq (, $(BOARD_WHITELIST))
     ifeq (, $(filter $(BOARD_WHITELIST), $(BOARD)))
-      $(shell $(COLOR_ECHO) "$(COLOR_RED)The selected BOARD=${BOARD} is not whitelisted:$(COLOR_RESET) ${BOARD_WHITELIST}" 1>&2)
+      $(shell $(COLOR_ECHO) "$(COLOR_RED)The selected BOARD=$(BOARD) is not whitelisted:$(COLOR_RESET) $(BOARD_WHITELIST)" 1>&2)
       EXPECT_ERRORS := 1
     endif
   endif
@@ -521,7 +521,7 @@ ifneq (, $(filter all, $(if $(MAKECMDGOALS), $(MAKECMDGOALS), all)))
   # If there is a blacklist, then test if the board is blacklisted.
   ifneq (, $(BOARD_BLACKLIST))
     ifneq (, $(filter $(BOARD_BLACKLIST), $(BOARD)))
-      $(shell $(COLOR_ECHO) "$(COLOR_RED)The selected BOARD=${BOARD} is blacklisted:$(COLOR_RESET) ${BOARD_BLACKLIST}" 1>&2)
+      $(shell $(COLOR_ECHO) "$(COLOR_RED)The selected BOARD=$(BOARD) is blacklisted:$(COLOR_RESET) $(BOARD_BLACKLIST)" 1>&2)
       EXPECT_ERRORS := 1
     endif
   endif
@@ -541,13 +541,13 @@ else # RIOT_VERSION
   export __RIOTBUILD_FLAG := RIOT
 
   NUM_RIOT_VERSION := $(shell cd $(RIOTBASE) && git rev-parse --verify --short "$(RIOT_VERSION)" 2>/dev/null)
-  ifeq (, ${NUM_RIOT_VERSION})
+  ifeq (, $(NUM_RIOT_VERSION))
     $(error The supplied RIOT_VERSION=$(RIOT_VERSION) is invalid!)
   endif
 
-  all $(filter-out clean, ${MAKECMDGOALS}): ..delegate
+  all $(filter-out clean, $(MAKECMDGOALS)): ..delegate
   ifneq (, $(filter clean, $(MAKECMDGOALS)))
-    all $(filter-out clean, ${MAKECMDGOALS}): clean
+    all $(filter-out clean, $(MAKECMDGOALS)): clean
   endif
 
   clean:
@@ -559,9 +559,9 @@ else # RIOT_VERSION
 	$(Q)cd $(RIOTBASE) && git archive --format=tar $(NUM_RIOT_VERSION) | ( cd $(@D) && tar x 1>&2 )
 
   ..delegate: $(BINDIR)/riot-version/$(NUM_RIOT_VERSION)/Makefile.include
-	@$(COLOR_ECHO) '$(COLOR_GREEN)Using RIOT_VERSION=${NUM_RIOT_VERSION}$(COLOR_RESET)' 1>&2
+	@$(COLOR_ECHO) '$(COLOR_GREEN)Using RIOT_VERSION=$(NUM_RIOT_VERSION)$(COLOR_RESET)' 1>&2
 	@$(COLOR_ECHO)
-	$(MAKE) RIOTBASE=$(<D) $(filter-out clean, ${MAKECMDGOALS})
+	$(MAKE) RIOTBASE=$(<D) $(filter-out clean, $(MAKECMDGOALS))
 
 endif
 

boards/common/arduino-mkr/Makefile.include

@@ -12,7 +12,7 @@ include $(RIOTMAKE)/tools/serial.inc.mk
 # setup the flash tool used
 ifeq ($(PROGRAMMER),jlink)
   # in case J-Link is attached to SWD pins, use a plain CPU memory model
-  export JLINK_DEVICE := ${MKR_JLINK_DEVICE}
+  export JLINK_DEVICE := $(MKR_JLINK_DEVICE)
   include $(RIOTMAKE)/tools/jlink.inc.mk
 else
   # by default, we use BOSSA to flash this board and take into account the

boards/common/msba2/tools/Makefile

@@ -5,10 +5,10 @@ prefix=/usr/local
 all: lpc2k_pgm pseudoterm
 
 SRC  = lpc2k_pgm.c download.c uuencode.c ihex.c serial.c chipinfo.c boot_2xxx.c boot_23xx.c control_2xxx.c
-OBJS = ${addprefix obj/,${patsubst %.c,%.o,$(SRC)}}
+OBJS = $(addprefix obj/,$(patsubst %.c,%.o,$(SRC)))
 
 PSEUDOTERM_SRC = pseudoterm.c serial.c control_2xxx.c
-PSEUDOTERM_OBJS = ${addprefix obj/,${patsubst %.c,%.o,$(PSEUDOTERM_SRC)}}
+PSEUDOTERM_OBJS = $(addprefix obj/,$(patsubst %.c,%.o,$(PSEUDOTERM_SRC)))
 
 TARGETDIR = bin
 

boards/native/Makefile.include

@@ -112,7 +112,7 @@ term-valgrind: export VALGRIND_FLAGS ?= \
 	--fullpath-after=$(RIOTBASE)/ \
 	--read-var-info=yes
 debug-valgrind-server: export VALGRIND_FLAGS ?= --vgdb=yes --vgdb-error=0 -v \
-	--leak-check=full --track-origins=yes --fullpath-after=${RIOTBASE} \
+	--leak-check=full --track-origins=yes --fullpath-after=$(RIOTBASE) \
 	--read-var-info=yes
 term-cachegrind: export CACHEGRIND_FLAGS += --tool=cachegrind
 term-gprof: export TERMPROG = GMON_OUT_PREFIX=gmon.out $(ELFFILE)
@@ -171,8 +171,8 @@ debug-valgrind-server:
 	$(VALGRIND) $(VALGRIND_FLAGS) $(ELFFILE) $(PORT)
 
 debug-valgrind:
-	$(eval VALGRIND_PID ?= $(shell pgrep -n memcheck-x86-li -u ${USER} | cut -d" " -f1))
+	$(eval VALGRIND_PID ?= $(shell pgrep -n memcheck-x86-li -u $(USER) | cut -d" " -f1))
-	$(eval DEBUGGER_FLAGS := -ex "target remote | vgdb --pid=${VALGRIND_PID}" $(DEBUGGER_FLAGS))
+	$(eval DEBUGGER_FLAGS := -ex "target remote | vgdb --pid=$(VALGRIND_PID)" $(DEBUGGER_FLAGS))
 	$(DEBUGGER) $(DEBUGGER_FLAGS)
 
 term-cachegrind:

doc/doxygen/Makefile

@@ -3,7 +3,7 @@ RIOTBASE=$(shell git rev-parse --show-toplevel)
 export STRIP_FROM_INC_PATH_LIST=$(shell \
     git ls-tree -dr --full-tree --name-only HEAD core drivers sys |\
     grep '/include$$' |\
-    sed 's/.*/\"$(subst /,\/,${RIOTBASE})\/\0\"/')
+    sed 's/.*/\"$(subst /,\/,$(RIOTBASE))\/\0\"/')
 
 # use lessc (http://lesscss.org/#using-less) for compiling CSS, alternatively
 # fall back to lesscpy (https://github.com/lesscpy/lesscpy)

drivers/Makefile

@@ -1,3 +1,3 @@
-DIRS += $(dir $(wildcard $(addsuffix /Makefile, ${USEMODULE})))
+DIRS += $(dir $(wildcard $(addsuffix /Makefile, $(USEMODULE))))
 
 include $(RIOTBASE)/Makefile.base

makefiles/buildtests.inc.mk

@@ -7,14 +7,14 @@ buildtest:
 	@ \
 	RESULT=true ; \
 	for board in $(BOARDS); do \
-		${COLOR_ECHO} -n "Building for $$board ... " ; \
+		$(COLOR_ECHO) -n "Building for $$board ... " ; \
 		BOARD=$${board} RIOT_CI_BUILD=1 RIOT_VERSION_OVERRIDE=buildtest \
 			$(MAKE) clean all -j $(NPROC) >/dev/null 2>&1; \
 		RES=$$? ; \
 		if [ $$RES -eq 0 ]; then \
-			${COLOR_ECHO} "$(COLOR_GREEN)success.${COLOR_RESET}" ; \
+			$(COLOR_ECHO) "$(COLOR_GREEN)success.$(COLOR_RESET)" ; \
 		else \
-			${COLOR_ECHO} "$(COLOR_RED)failed!${COLOR_RESET}" ; \
+			$(COLOR_ECHO) "$(COLOR_RED)failed!$(COLOR_RESET)" ; \
 			RESULT=false ; \
 		fi ; \
 		$(MAKE) clean-intermediates >/dev/null 2>&1 || true; \

makefiles/cflags.inc.mk

@@ -51,7 +51,7 @@ CXXUWFLAGS += -std=%
 ifeq ($(LTO),1)
   $(warning Building with Link-Time-Optimizations is currently an experimental feature. Expect broken binaries.)
   LTOFLAGS = -flto
-  LINKFLAGS += ${LTOFLAGS}
+  LINKFLAGS += $(LTOFLAGS)
 endif
 
 # Forbid common symbols to prevent accidental aliasing.

makefiles/docker.inc.mk

@@ -87,7 +87,7 @@ DOCKER_OVERRIDE_CMDLINE := $(strip $(DOCKER_OVERRIDE_CMDLINE))
 # The `flash`, `term`, `debugserver` etc. targets usually require access to
 # hardware which may not be reachable from inside the container.
 ..in-docker-container:
-	@$(COLOR_ECHO) '${COLOR_GREEN}Launching build container using image "$(DOCKER_IMAGE)".${COLOR_RESET}'
+	@$(COLOR_ECHO) '$(COLOR_GREEN)Launching build container using image "$(DOCKER_IMAGE)".$(COLOR_RESET)'
 	docker run $(DOCKER_FLAGS) -t -u "$$(id -u)" \
 	    -v '$(RIOTBASE):$(DOCKER_BUILD_ROOT)/riotbase' \
 	    -v '$(RIOTCPU):$(DOCKER_BUILD_ROOT)/riotcpu' \

makefiles/info-global.inc.mk

@@ -8,7 +8,7 @@ FEATURES_OPTIONAL_GLOBAL := $(FEATURES_OPTIONAL)
 DISABLE_MODULE_GLOBAL := $(DISABLE_MODULE_GLOBAL)
 
 define board_missing_features
-  BOARD             := ${1}
+  BOARD             := $(1)
   USEMODULE         := $(USEMODULE_GLOBAL)
   USEPKG            := $(USEPKG_GLOBAL)
   DISABLE_MODULE    := $(DISABLE_MODULE_GLOBAL)
@@ -16,21 +16,21 @@ define board_missing_features
   FEATURES_OPTIONAL := $(FEATURES_OPTIONAL_GLOBAL)
   FEATURES_MISSING  :=
   FEATURES_PROVIDED :=
-  include $${RIOTBOARD}/${1}/Makefile.features
+  include $$(RIOTBOARD)/$(1)/Makefile.features
   ifdef BUILDTEST_MCU_GROUP
     ifneq ($(BUILDTEST_MCU_GROUP), $$(FEATURES_MCU_GROUP))
-      BOARDS_FEATURES_MISSING += "${1} ${BUILDTEST_MCU_GROUP}"
+      BOARDS_FEATURES_MISSING += "$(1) $(BUILDTEST_MCU_GROUP)"
-    BOARDS_WITH_MISSING_FEATURES += ${1}
+    BOARDS_WITH_MISSING_FEATURES += $(1)
     endif
   endif
 
   include $(RIOTBASE)/Makefile.dep
 
   FEATURES_MISSING := $$(sort $$(filter-out $$(FEATURES_PROVIDED), $$(FEATURES_REQUIRED)))
-  ifneq (, $${FEATURES_MISSING})
+  ifneq (, $$(FEATURES_MISSING))
-    BOARDS_FEATURES_MISSING += "${1} $${FEATURES_MISSING}"
+    BOARDS_FEATURES_MISSING += "$(1) $$(FEATURES_MISSING)"
     ifneq (, $$(filter-out $$(FEATURES_OPTIONAL), $$(FEATURES_MISSING)))
-      BOARDS_WITH_MISSING_FEATURES += ${1}
+      BOARDS_WITH_MISSING_FEATURES += $(1)
     endif
   endif
 endef
@@ -47,14 +47,14 @@ BOARDS := $(filter-out $(BOARDS_WITH_MISSING_FEATURES), $(BOARDS))
 info-buildsizes: SHELL=bash
 info-buildsizes:
 	@echo -e "   text\t   data\t    bss\t    dec\tboard"; \
-	for board in ${BOARDS}; do \
+	for board in $(BOARDS); do \
 	    echo "$$(BOARD=$${board} $(MAKE) --no-print-directory info-buildsize 2>/dev/null | tail -n-1 | cut -f-4)" "$${board}"; \
 	done;
 
 info-buildsizes-diff: SHELL=bash
 info-buildsizes-diff:
 	@echo -e "text\tdata\tbss\tdec\tBOARD/BINDIRBASE\n"; \
-	for board in ${BOARDS}; do \
+	for board in $(BOARDS); do \
 	  for BINDIRBASE in $${OLDBIN} $${NEWBIN}; do \
 	      BINDIRBASE=$${BINDIRBASE} BOARD=$${board} $(MAKE) info-buildsize --no-print-directory 2>/dev/null | tail -n-1 | cut -f-4; \
 	  done | \
@@ -62,16 +62,16 @@ info-buildsizes-diff:
 	    for I in 0 1 2 3; do \
 	      if [[ -n "$${NEW[I]}" && -n "$${OLD[I]}" ]]; then \
 	        DIFF=$$(($${NEW[I]} - $${OLD[I]})); \
-	        if [[ "$${DIFF}" -gt 0 ]]; then $(COLOR_ECHO) -n "${COLOR_RED}"; fi; \
+	        if [[ "$${DIFF}" -gt 0 ]]; then $(COLOR_ECHO) -n "$(COLOR_RED)"; fi; \
-	        if [[ "$${DIFF}" -lt 0 ]]; then $(COLOR_ECHO) -n "${COLOR_GREEN}"; fi; \
+	        if [[ "$${DIFF}" -lt 0 ]]; then $(COLOR_ECHO) -n "$(COLOR_GREEN)"; fi; \
 	      else \
-	        DIFF="${COLOR_RED}ERR"; \
+	        DIFF="$(COLOR_RED)ERR"; \
 	      fi; \
-	      echo -ne "$${DIFF}\t${COLOR_RESET}"; \
+	      echo -ne "$${DIFF}\t$(COLOR_RESET)"; \
 	    done; \
 	    echo "$${board}"; \
-	    for I in 0 1 2 3; do echo -ne "$${OLD[I]-${COLOR_RED}ERR${COLOR_RESET}}\t"; done; echo -e "$${OLDBIN}"; \
+	    for I in 0 1 2 3; do echo -ne "$${OLD[I]-$(COLOR_RED)ERR$(COLOR_RESET)}\t"; done; echo -e "$${OLDBIN}"; \
-	    for I in 0 1 2 3; do echo -ne "$${NEW[I]-${COLOR_RED}ERR${COLOR_RESET}}\t"; done; echo -e "$${NEWBIN}\n"; \
+	    for I in 0 1 2 3; do echo -ne "$${NEW[I]-$(COLOR_RED)ERR$(COLOR_RESET)}\t"; done; echo -e "$${NEWBIN}\n"; \
 	  done; \
 	done;
 

makefiles/info-nproc.inc.mk

@@ -19,10 +19,10 @@ ifneq (, $(filter buildtest info-concurrency, $(MAKECMDGOALS)))
     NPROC := $(shell echo $$(($(NPROC) + 1)))
 
     ifneq (, $(NPROC_MAX))
-      NPROC := $(shell if [ ${NPROC} -gt $(NPROC_MAX) ]; then echo $(NPROC_MAX); else echo ${NPROC}; fi)
+      NPROC := $(shell if [ $(NPROC) -gt $(NPROC_MAX) ]; then echo $(NPROC_MAX); else echo $(NPROC); fi)
     endif
     ifneq (, $(NPROC_MIN))
-      NPROC := $(shell if [ ${NPROC} -lt $(NPROC_MIN) ]; then echo $(NPROC_MIN); else echo ${NPROC}; fi)
+      NPROC := $(shell if [ $(NPROC) -lt $(NPROC_MIN) ]; then echo $(NPROC_MIN); else echo $(NPROC); fi)
     endif
   endif
 endif

makefiles/info.inc.mk

@@ -3,7 +3,7 @@
         info-features-provided info-features-required
 
 info-objsize:
-	@case "${SORTROW}" in \
+	@case "$(SORTROW)" in \
 	  text) SORTROW=1 ;; \
 	  data) SORTROW=2 ;; \
 	  bss) SORTROW=3 ;; \

makefiles/mcuboot.mk

@@ -23,7 +23,7 @@ endif
 
 mcuboot: mcuboot-create-key link
 	@$(COLOR_ECHO)
-	@$(COLOR_ECHO) '${COLOR_PURPLE}Re-linking for MCUBoot at $(MCUBOOT_SLOT0_SIZE)...${COLOR_RESET}'
+	@$(COLOR_ECHO) '$(COLOR_PURPLE)Re-linking for MCUBoot at $(MCUBOOT_SLOT0_SIZE)...$(COLOR_RESET)'
 	@$(COLOR_ECHO)
 	$(Q)$(_LINK) $(LINKFLAGPREFIX)--defsym=offset="$$(($(MCUBOOT_SLOT0_SIZE) + $(IMAGE_HDR_SIZE)))" \
 	$(LINKFLAGPREFIX)--defsym=length="$$(($(MCUBOOT_SLOT1_SIZE) - $(IMAGE_HDR_SIZE)))" \
@@ -32,8 +32,8 @@ mcuboot: mcuboot-create-key link
 	$(IMGTOOL) sign --key $(MCUBOOT_KEYFILE) --version $(IMAGE_VERSION) --align \
 	$(MCUBOOT_IMAGE_ALIGN) -H $(IMAGE_HDR_SIZE) $(BINFILE) $(SIGN_BINFILE)
 	@$(COLOR_ECHO)
-	@$(COLOR_ECHO) '${COLOR_PURPLE}Signed with $(MCUBOOT_KEYFILE) for version $(IMAGE_VERSION)\
+	@$(COLOR_ECHO) '$(COLOR_PURPLE)Signed with $(MCUBOOT_KEYFILE) for version $(IMAGE_VERSION)\
-	${COLOR_RESET}'
+	$(COLOR_RESET)'
 	@$(COLOR_ECHO)
 
 $(MCUBOOT_BIN):

sys/Makefile

@@ -125,6 +125,6 @@ ifneq (,$(filter nanocoap,$(USEMODULE)))
   DIRS += net/application_layer/nanocoap
 endif
 
-DIRS += $(dir $(wildcard $(addsuffix /Makefile, ${USEMODULE})))
+DIRS += $(dir $(wildcard $(addsuffix /Makefile, $(USEMODULE))))
 
 include $(RIOTBASE)/Makefile.base

sys/crypto/Makefile

@@ -1,7 +1,7 @@
-ifeq (, ${RIOT_CHACHA_PRNG_DEFAULT})
+ifeq (, $(RIOT_CHACHA_PRNG_DEFAULT))
     RIOT_CHACHA_PRNG_DEFAULT := $(shell head -c 64 /dev/urandom | hexdump -e '"0x%4xull,"')
 endif
 
-CFLAGS += -DRIOT_CHACHA_PRNG_DEFAULT="${RIOT_CHACHA_PRNG_DEFAULT}"
+CFLAGS += -DRIOT_CHACHA_PRNG_DEFAULT="$(RIOT_CHACHA_PRNG_DEFAULT)"
 
 include $(RIOTBASE)/Makefile.base

sys/log/Makefile

@@ -1,3 +1,3 @@
-DIRS += $(dir $(wildcard $(addsuffix /Makefile, ${USEMODULE})))
+DIRS += $(dir $(wildcard $(addsuffix /Makefile, $(USEMODULE))))
 
 include $(RIOTBASE)/Makefile.base

tests/driver_dsp0401/Makefile

@@ -3,6 +3,6 @@ include ../Makefile.tests_common
 USEMODULE += dsp0401
 
 LOOPS ?= 3
-CFLAGS += -DLOOPS=${LOOPS}
+CFLAGS += -DLOOPS=$(LOOPS)
 
 include $(RIOTBASE)/Makefile.include

tests/driver_sx127x/Makefile

@@ -13,7 +13,7 @@ USEMODULE += xtimer
 DRIVER ?= sx1276
 
 # use SX1276 by default
-USEMODULE += ${DRIVER}
+USEMODULE += $(DRIVER)
 
 FEATURES_REQUIRED ?= periph_spi
 FEATURES_REQUIRED ?= periph_gpio