diff --git a/boards/arduino-mkr-common/Makefile.include b/boards/arduino-mkr-common/Makefile.include
index 9fc74857d2bb22b16297011779c2f2537f8f099b..8796cd009643448e7ac90d125396594986397079 100644
--- a/boards/arduino-mkr-common/Makefile.include
+++ b/boards/arduino-mkr-common/Makefile.include
@@ -11,13 +11,13 @@ 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}
-    include $(RIOTMAKE)/tools/jlink.inc.mk
+  # in case J-Link is attached to SWD pins, use a plain CPU memory model
+  export JLINK_DEVICE := ${MKR_JLINK_DEVICE}
+  include $(RIOTMAKE)/tools/jlink.inc.mk
 else
-    # on default, we use BOSSA to flash this board
-    export LINKER_SCRIPT ?= $(RIOTCPU)/sam0_common/ldscripts/$(CPU_MODEL)_mkr.ld
-    include $(RIOTMAKE)/tools/bossa.inc.mk
+  # on default, we use BOSSA to flash this board
+  export LINKER_SCRIPT ?= $(RIOTCPU)/sam0_common/ldscripts/$(CPU_MODEL)_mkr.ld
+  include $(RIOTMAKE)/tools/bossa.inc.mk
 endif
 
 INCLUDES += -I$(RIOTBOARD)/arduino-mkr-common/include
diff --git a/boards/msb-430-common/Makefile.include b/boards/msb-430-common/Makefile.include
index 51ed1df09a27f72b44d85755e7b486930d49b627..7a9d36b5b3d5f19dcc287d5c2087e002b781023f 100644
--- a/boards/msb-430-common/Makefile.include
+++ b/boards/msb-430-common/Makefile.include
@@ -13,7 +13,7 @@ export OFLAGS = -O ihex
 export PROGRAMMER ?= olimex
 export MSPDEBUGFLAGS += -j $(PROGRAMMER)
 ifeq ($(strip $(PROGRAMMER)),uif)
-    export MSPDEBUGFLAGS += -d $(PORT)
+  export MSPDEBUGFLAGS += -d $(PORT)
 endif
 export FLASHER ?= mspdebug
 export FFLAGS = $(MSPDEBUGFLAGS) "prog $(HEXFILE)"
diff --git a/boards/msba2-common/Makefile.include b/boards/msba2-common/Makefile.include
index c62a1017a35ca796038a5d04aae840a7dd9d3821..c1a340a7b1956466002173438b259ed31669f722 100644
--- a/boards/msba2-common/Makefile.include
+++ b/boards/msba2-common/Makefile.include
@@ -22,7 +22,7 @@ export LINKFLAGS += -Wl,--gc-sections
 USEMODULE += newlib_nano
 
 ifeq ($(PORT),)
-	export PORT = /dev/ttyUSB0
+  export PORT = /dev/ttyUSB0
 endif
 export FFLAGS = $(PORT) $(HEXFILE)
 
diff --git a/boards/msba2/Makefile.include b/boards/msba2/Makefile.include
index f7d05c148dbb9ab517d5af4675d39bf5ea668662..c25d470b1935dfc23eaf5213857fdc6199c46bce 100644
--- a/boards/msba2/Makefile.include
+++ b/boards/msba2/Makefile.include
@@ -1,5 +1,5 @@
 ifneq (,$(filter netdev_default gnrc_netdev_default,$(USEMODULE)))
-	USEMODULE += cc110x
+  USEMODULE += cc110x
 endif
 
 USEMODULE += msba2-common
diff --git a/boards/native/Makefile.include b/boards/native/Makefile.include
index a339978daf673373b8a7e52c612d05c53384b8ab..8bcefd50dc37633037266bda21f9d0144df6ed35 100644
--- a/boards/native/Makefile.include
+++ b/boards/native/Makefile.include
@@ -12,33 +12,37 @@ USEMODULE += native-drivers
 export PREFIX =
 export CC ?= $(PREFIX)gcc
 export CXX ?= $(PREFIX)g++
+
 ifeq ($(LTO),1)
-export AR = $(PREFIX)gcc-ar
+  export AR = $(PREFIX)gcc-ar
 else
-export AR = $(PREFIX)ar
+  export AR = $(PREFIX)ar
 endif
+
 export AS ?= $(PREFIX)as
 export LINK ?= $(PREFIX)gcc
 export SIZE ?= $(PREFIX)size
+
 ifneq ($(shell uname -s),Darwin)
-export OBJCOPY ?= $(PREFIX)objcopy
-else
-ifeq (0,$(shell which gobjcopy 2>&1 > /dev/null ; echo $$?))
-export OBJCOPY ?= gobjcopy
-export OFLAGS ?= -O ihex
+  export OBJCOPY ?= $(PREFIX)objcopy
 else
-# If gobjcopy is not available, just create an empty file. The hexfile
-# is not used for native anyways.
-export OBJCOPY ?= touch
-export OFLAGS =
-endif
+  ifeq (0,$(shell which gobjcopy 2>&1 > /dev/null ; echo $$?))
+    export OBJCOPY ?= gobjcopy
+    export OFLAGS ?= -O ihex
+  else
+    # If gobjcopy is not available, just create an empty file. The hexfile
+    # is not used for native anyways.
+    export OBJCOPY ?= touch
+    export OFLAGS =
+  endif
 endif
 
 ifeq ($(shell uname -s),Darwin)
-export DEBUGGER ?= lldb
+  export DEBUGGER ?= lldb
 else
-export DEBUGGER ?= gdb
+  export DEBUGGER ?= gdb
 endif
+
 export TERMPROG ?= $(ELF)
 export FLASHER = true
 export VALGRIND ?= valgrind
@@ -47,19 +51,20 @@ export GPROF ?= gprof
 
 # basic cflags:
 export CFLAGS += -Wall -Wextra -pedantic -std=gnu99
+
 ifeq ($(shell uname -m),x86_64)
-export CFLAGS += -m32
+  export CFLAGS += -m32
 endif
 ifneq (,$(filter -DDEVELHELP,$(CFLAGS)))
-export CFLAGS += -fstack-protector-all
+  export CFLAGS += -fstack-protector-all
 endif
 ifeq ($(shell uname -s),FreeBSD)
-ifeq ($(shell uname -m),amd64)
-export CFLAGS += -m32 -DCOMPAT_32BIT -B/usr/lib32
-endif
+  ifeq ($(shell uname -m),amd64)
+    export CFLAGS += -m32 -DCOMPAT_32BIT -B/usr/lib32
+  endif
 endif
 ifeq ($(shell uname -s),Darwin)
-export CFLAGS += -Wno-deprecated-declarations
+  export CFLAGS += -Wno-deprecated-declarations
 endif
 
 # unwanted (CXXUWFLAGS) and extra (CXXEXFLAGS) flags for c++
@@ -67,40 +72,40 @@ export CXXUWFLAGS +=
 export CXXEXFLAGS +=
 
 ifeq ($(shell uname -m),x86_64)
-export LINKFLAGS += -m32
+  export LINKFLAGS += -m32
 endif
 ifeq ($(shell uname -s),FreeBSD)
-ifeq ($(shell uname -m),amd64)
-export LINKFLAGS += -m32 -DCOMPAT_32BIT -L/usr/lib32 -B/usr/lib32
-endif
-export LINKFLAGS += -L $(BINDIR)
+  ifeq ($(shell uname -m),amd64)
+    export LINKFLAGS += -m32 -DCOMPAT_32BIT -L/usr/lib32 -B/usr/lib32
+  endif
+  export LINKFLAGS += -L $(BINDIR)
 else
-export LINKFLAGS += -ldl
+  export LINKFLAGS += -ldl
 endif
 
 # clean up unused functions
 export CFLAGS += -ffunction-sections -fdata-sections
 ifeq ($(shell uname -s),Darwin)
-export LINKFLAGS += -Wl,-dead_strip
+  export LINKFLAGS += -Wl,-dead_strip
 else
-export LINKFLAGS += -Wl,--gc-sections
+  export LINKFLAGS += -Wl,--gc-sections
 endif
 export LINKFLAGS += -ffunction-sections
 
 # set the tap interface for term/valgrind
 ifneq (,$(filter netdev_default gnrc_netdev_default,$(USEMODULE)))
-	export PORT ?= tap0
+  export PORT ?= tap0
 else
-	export PORT =
+  export PORT =
 endif
 
 export TERMFLAGS := $(PORT) $(TERMFLAGS)
 
 export ASFLAGS =
 ifeq ($(shell basename $(DEBUGGER)),lldb)
-export DEBUGGER_FLAGS = -- $(ELF) $(TERMFLAGS)
+  export DEBUGGER_FLAGS = -- $(ELF) $(TERMFLAGS)
 else
-export DEBUGGER_FLAGS = -q --args $(ELF) $(TERMFLAGS)
+  export DEBUGGER_FLAGS = -q --args $(ELF) $(TERMFLAGS)
 endif
 term-valgrind: export VALGRIND_FLAGS ?= \
 	--leak-check=full \
@@ -128,24 +133,24 @@ export CFLAGS += -DDEBUG_ASSERT_VERBOSE
 
 # workaround for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52624
 ifneq ($(shell gcc --version | head -1 | grep -E ' (4.6|4.7)'),)
-	export CFLAGS += -DHAVE_NO_BUILTIN_BSWAP16
+  export CFLAGS += -DHAVE_NO_BUILTIN_BSWAP16
 endif
 
 # backward compatability with glibc <= 2.17 for native
 ifeq ($(CPU),native)
-ifeq ($(shell uname -s),Linux)
-ifeq ($(shell ldd --version |  awk '/^ldd/{if ($$NF < 2.17) {print "yes"} else {print "no"} }'),yes)
-	LINKFLAGS += -lrt
-endif
-endif
+  ifeq ($(shell uname -s),Linux)
+    ifeq ($(shell ldd --version |  awk '/^ldd/{if ($$NF < 2.17) {print "yes"} else {print "no"} }'),yes)
+	  LINKFLAGS += -lrt
+    endif
+  endif
 endif
 
 # clumsy way to enable building native on osx:
 BUILDOSXNATIVE = 0
 ifeq ($(CPU),native)
-ifeq ($(shell uname -s),Darwin)
-	BUILDOSXNATIVE = 1
-endif
+  ifeq ($(shell uname -s),Darwin)
+    BUILDOSXNATIVE = 1
+  endif
 endif
 
 all: # do not override first target
diff --git a/boards/nrf52840dk/Makefile.include b/boards/nrf52840dk/Makefile.include
index 298a57058d3733deafa2309119bde8e0273386c3..485d3f04fbea812e2a71da17a3a8517284bfc150 100644
--- a/boards/nrf52840dk/Makefile.include
+++ b/boards/nrf52840dk/Makefile.include
@@ -11,9 +11,9 @@ export JLINK_DEVICE := nrf52
 
 # special options when using SoftDevice
 ifneq (,$(filter nordic_softdevice_ble,$(USEPKG)))
-export JLINK_PRE_FLASH := erase\nloadfile $(BINDIR)/softdevice.hex
-export FLASH_ADDR := 0x1f000
-export LINKER_SCRIPT ?= $(RIOTCPU)/$(CPU)/ldscripts/$(CPU_MODEL)_sd.ld
+  export JLINK_PRE_FLASH := erase\nloadfile $(BINDIR)/softdevice.hex
+  export FLASH_ADDR := 0x1f000
+  export LINKER_SCRIPT ?= $(RIOTCPU)/$(CPU)/ldscripts/$(CPU_MODEL)_sd.ld
 endif
 include $(RIOTMAKE)/tools/jlink.inc.mk
 
diff --git a/boards/pba-d-01-kw2x/Makefile.include b/boards/pba-d-01-kw2x/Makefile.include
index c32e7fdaeec681836ad2013179f55ae9790998bd..637cd2b8f7e24e9fcac49c142003c67bb1cadfa4 100644
--- a/boards/pba-d-01-kw2x/Makefile.include
+++ b/boards/pba-d-01-kw2x/Makefile.include
@@ -34,12 +34,12 @@ export PRE_FLASH_CHECK_SCRIPT = $(RIOTCPU)/kinetis_common/dist/check-fcfield-elf
 # Use /dist/tools/usb-serial/list-ttys.sh to find out serial number.
 #   Usage: SERIAL="0200..." BOARD="pba-d-01-kw2x" make flash
 ifneq (,$(SERIAL))
-    export OPENOCD_EXTRA_INIT += "-c cmsis_dap_serial $(SERIAL)"
-    SERIAL_TTY = $(firstword $(shell $(RIOTBASE)/dist/tools/usb-serial/find-tty.sh $(SERIAL)))
-    ifeq (,$(SERIAL_TTY))
-        $(error Did not find a device with serial $(SERIAL))
-    endif
-    PORT_LINUX := $(SERIAL_TTY)
+  export OPENOCD_EXTRA_INIT += "-c cmsis_dap_serial $(SERIAL)"
+  SERIAL_TTY = $(firstword $(shell $(RIOTBASE)/dist/tools/usb-serial/find-tty.sh $(SERIAL)))
+  ifeq (,$(SERIAL_TTY))
+    $(error Did not find a device with serial $(SERIAL))
+  endif
+  PORT_LINUX := $(SERIAL_TTY)
 endif
 
 # setup serial terminal
diff --git a/boards/waspmote-pro/Makefile.include b/boards/waspmote-pro/Makefile.include
index 7e3e58f9fc6657f075ebcdc3115de4ed5d36c731..eae5e716a32635b9c0b4f114ec3773136b1dd71a 100644
--- a/boards/waspmote-pro/Makefile.include
+++ b/boards/waspmote-pro/Makefile.include
@@ -30,7 +30,7 @@ export DEBUGGER = $(DIST_PATH)/debug.sh $(DEBUGSERVER_FLAGS) $(DIST_PATH) $(DEBU
 export PROGRAMMER ?= stk500v1
 
 ifeq ($(PROGRAMMER), stk500v1)
-    export PROGRAMMER_FLAGS = -P $(PORT) -b 115200
+  export PROGRAMMER_FLAGS = -P $(PORT) -b 115200
 endif
 
 export OFLAGS += -j .text -j .data -O ihex
diff --git a/boards/x86-multiboot-common/Makefile.include b/boards/x86-multiboot-common/Makefile.include
index 4133f13305ac18c4f560dcd6763c02d520a2fde3..1eb877a67b5f7350713c6c8cb46a3f33075b542d 100644
--- a/boards/x86-multiboot-common/Makefile.include
+++ b/boards/x86-multiboot-common/Makefile.include
@@ -34,9 +34,9 @@ export CPU = x86
 # toolchain config
 export CC ?= $(PREFIX)gcc
 ifeq ($(LTO),1)
-export AR = $(PREFIX)gcc-ar
+  export AR = $(PREFIX)gcc-ar
 else
-export AR = $(PREFIX)ar
+  export AR = $(PREFIX)ar
 endif
 export AS ?= $(PREFIX)as
 export RANLIB ?= $(PREFIX)ranlib