[En-Nut-Discussion] Readability modification to Makefiles

[Ulrich Prinz]

Hehe... yes I know...

I modified it in some other places too, so if you compile your project,
it states at the first line, what project it compiles and then it gives
the compiler calling parameters _one_ time.

I needed that on my own, as I have one code for 8 different sensor
boards. So depending on what sensor I need, I call
make BOARD=xx_yy_zzz clean all burn
and I get
Buidling: Sensor
CFLAGS: -I../include  -DAT91SAM7X_EK -DAT91_PLL_MAINCK="18432000"
-DNUTMEM_SIZE="0xFF00" -DNUTMEM_START="0x00200100" -DBOARD=xx_yy_zzz
-DNUT_THREAD_IDLESTACK="512" -DNUT_THREAD_MAINSTACK="1024"
-DNUT_THREAD_TCPSMSTACK="1024" -DNUT_THREAD_DHCPSTACK="1024"
-DNUT_THREAD_SNTPSTACK="1024" -DFOPEN_MAX=20 -DPHAT_SECTOR_BUFFERS="6"
-DNIC_PHY_ADDR=1 -DMMC_CS_BIT=SPI0_NPCS3_PA09B -DNUT_WDT_START=yes
-DMCU_AT91=yes -DMCU_AT91SAM7X=yes -DNUTLUA_STRLIB_IS_STANDARD=yes
-DNUTLUA_MATHLIB_IS_STANDARD=yes -DNUTLUA_TABLIB_IS_STANDARD=yes
-DNUTLUA_OPTIMIZE_MEMORY=2 -DNUTLUA_FLOATING_POINT -DLIB_HEAPSIZE=8192
-DNUT_CPU_FREQ="55000073" -DPLL_MUL_VAL=1300 -DPLL_DIV_VAL=218  -mthumb
 -mcpu=arm7tdmi -mthumb-interwork -Os -Wall -Wstrict-prototypes -Werror
  [CC] main.c
  [CC] sensor.c
  ...

So I know what you mean. But it must not be sprayed on the screen that
you cannot find what you're looking for. In addition, due to different
length of directory and file names, the compiler output shifts forth and
back except you hack som other things into the makefiles to keep that
straight. But even then your eyes need a good pattern detection algorithm :)

But hey, there is no problem if you want some flexibility.
There are only a few lines needed to declare the called programs in a
makefile:

TRGT   = avr-

CC     = @$(TRGT)gcc
AR     = @$(TRGT)ar
LN     = @$(TRGT)gcc
CP     = @cp

So we could do it like this:
SILENT=@
CC = $(SILENT)$(TRGT)gcc

if you need the full output, call make SILENT= clean all burn

Another thing is that we should have a look on these variables at all.
All of them are evaluated and extracted at runtime any time they are
accessed as they are declared with '='. Most of them could be set as
fixed by declaring them ':=' what makes it obsolete to expand them every
time they are called. That may improve compiling on slower machines too.

For the doubts about having to add a @echo "..." line everywhere, there
is no problem. A good editor helps with his find/replace functions and I
already did it for any ARM/Cortex related makefile :) I only didn't commit.
As this is a big change I would check it in as a branch for Harald and
others to check it is working. Then I would merge it to trunk.

Best regards
Ulrich