make: move exported make vars to one place

Makefile.buildtests

@@ -171,7 +171,11 @@ buildinfo:
 	@echo 'HEXFILE: $(HEXFILE)'
 	@echo ''
 	@echo 'CC:      $(CC)'
-	@echo -e 'CFLAGSS:$(patsubst %, \n\t%, $(CFLAGS))'
+	@echo -e 'CFLAGS:$(patsubst %, \n\t%, $(CFLAGS))'
+	@echo ''
+	@echo 'CXX:     $(CXX)'
+	@echo -e 'CXXUWFLAGS:$(patsubst %, \n\t%, $(CXXUWFLAGS))'
+	@echo -e 'CXXEXFLAGS:$(patsubst %, \n\t%, $(CXXEXFLAGS))'
 	@echo ''
 	@echo 'LINK:    $(LINK)'
 	@echo -e 'LINKFLAGS:$(patsubst %, \n\t%, $(LINKFLAGS))'

Makefile.include

@@ -3,13 +3,13 @@ export __RIOTBUILD_FLAG := RIOT
 
 # set undefined variables
 RIOTBASE ?= $(shell dirname "$(lastword $(MAKEFILE_LIST))")
-export RIOTBASE := $(abspath $(RIOTBASE))
+RIOTBASE := $(abspath $(RIOTBASE))
 
 RIOTCPU ?= $(RIOTBASE)/cpu
-export RIOTCPU := $(abspath $(RIOTCPU))
+RIOTCPU := $(abspath $(RIOTCPU))
 
 RIOTBOARD ?= $(RIOTBASE)/boards
-export RIOTBOARD := $(abspath $(RIOTBOARD))
+RIOTBOARD := $(abspath $(RIOTBOARD))
 
 ifeq ($(strip $(MCU)),)
 	MCU = $(CPU)
@@ -32,11 +32,8 @@ BB = $(shell echo $(BOARD)|tr 'a-z' 'A-Z'|tr '-' '_')
 CPUDEF = $(shell echo $(CPU)|tr 'a-z' 'A-Z'|tr '-' '_')
 CFLAGS += -DBOARD_$(BB) -DCPU_$(CPUDEF)
 
-export CFLAGS
+BINDIRBASE ?= $(CURDIR)/bin
-export APPLICATION
+BINDIR ?= $(abspath $(BINDIRBASE)/$(BOARD))/
-
-export BINDIRBASE ?= $(CURDIR)/bin
-export BINDIR ?= $(abspath $(BINDIRBASE)/$(BOARD))/
 
 ifeq ($(QUIET),1)
 	AD=@
@@ -44,7 +41,6 @@ ifeq ($(QUIET),1)
 else
 	AD=
 endif
-export AD
 
 BOARD := $(strip $(BOARD))
 
@@ -87,13 +83,11 @@ BASELIBS += $(USEPKG:%=${BINDIR}%.a)
 
 .PHONY: all clean flash doc term objsize buildsize buildsizes buildsizes-diff buildinfo
 
-export ELFFILE ?= $(BINDIR)$(APPLICATION).elf
+ELFFILE ?= $(BINDIR)$(APPLICATION).elf
-export HEXFILE ?= $(ELFFILE:.elf=.hex)
+HEXFILE ?= $(ELFFILE:.elf=.hex)
 
 # variables used to complie and link c++
-export CPPMIX ?= $(if $(wildcard *.cpp),1,)
+CPPMIX ?= $(if $(wildcard *.cpp),1,)
-export CXXUWFLAGS
-export CXXEXFLAGS
 
 # We assume $(LINK) to be gcc-like. Use `LINKFLAGPREFIX :=` for ld-like linker options.
 LINKFLAGPREFIX ?= -Wl,
@@ -159,3 +153,6 @@ debug:
 
 # Extra make goals for testing and comparing changes.
 include $(RIOTBASE)/Makefile.buildtests
+
+# Export variables used throughout the whole make system:
+include $(RIOTBASE)/Makefile.vars

Makefile.vars

@@ -0,0 +1,42 @@
+export AD                    # Used in front of Makefile lines to suppress the printing of the command if user did not opt-in to see them.
+export QUIET                 # The parameter to use whether to show verbose makefile commands or not.
+
+export APPLICATION           # The application, set in the Makefile which is run by the user.
+export BOARD                 # The board to compile the application for.
+export CPU                   # The CPU, set by the board's Makefile.include.
+export MCU                   # The MCU, set by the board's Makefile.include, or defaulted to the same value as CPU.
+export INCLUDES              # The extra include paths, set by the various Makefile.include files.
+
+export USEMODULE             # Sys Module dependencies of the application. Set in the application's Makefile.
+export USEPKG                # Pkg dependencies (third party modules) of the application. Set in the application's Makefile.
+export DISABLE_MODULE        # Used in the application's Makefile to suppress DEFAULT_MODULEs.
+export APPDEPS               # Files / Makefile targets that need to be created before the application can be build. Set in the application's Makefile.
+
+export RIOTBASE              # The root folder of RIOT. The folder where this very file lives in.
+export RIOTCPU               # For third party CPUs this folder is the base of the CPUs.
+export RIOTBOARD             # For third party BOARDs this folder is the base of the BOARDs.
+export BINDIRBASE            # This is the folder where the application should be built in. For each BOARD a different subfolder is used.
+export BINDIR                # This is the folder where the application should be built in.
+
+export PREFIX                # The prefix of the toolchain commands, e.g. "arm-non-eabi-" or "msp430-".
+export CC                    # The C compiler to use.
+export CXX                   # The CXX compiler to use.
+export CFLAGS                # The compiler flags. Must only ever be used with `+=`.
+export CXXUWFLAGS            # (Patters of) flags in CFLAGS, that should not be passed to CXX.
+export CXXEXFLAGS            # Additional flags that should be passed to CXX.
+export AR                    # The command to create the object file archives.
+export AS                    # The assembler.
+export ASFLAGS               # Flags for the assembler.
+export LINK                  # The command used to link the files. Must take the same parameters as GCC, i.e. "ld" won't work.
+export LINKFLAGS             # Flags to supply in the linking step.
+export OBJCOPY               # The command used to create the HEXFILE.
+export OFLAGS                # The parameter for OBJCOPY, e.g. to strip the debug information.
+export SIZE                  # The command to read to size of the ELF sections.
+export UNDEF                 # Set by the BOARD's and CPU's Makefile.include, this contains object files with must not be used in the ELFFILE even if the if no call to the functions.
+
+export FLASHER               # The command to call on "make flash".
+export FFLAGS                # The parameters to supply to FLASHER.
+export TERMPROG              # The command to call on "make term".
+export PORT                  # The parameters to supply to TERMPROG.
+export ELFFILE               # The unstripped result of the compilation.
+export HEXFILE               # The stripped result of the compilation.