Application.mk:define main entry MAINNAME relatively

[xuxin930]

Summary

this patch fix issue #633

• issue
  when a program has multiple MAINSRC for incremental compilation, the PROGNAME of the compiled file may generate errors

 -------------------- compile definition error ---------------------
 cc -c -g CFLAGS INCLUDEDIR -Dmain=funA_main funB.c -o funB.c.path.o
                             ^^^^  ^^^^^^    ^^^^
-------------------------------------------------------------------

• solution
  we use the MAINOBJ:PROGNAME mapping variable to define the main entry name, for example:

# this is Makefile in apps/examples/myapp for some app
# two programs need to be compiled
MAINSRC = demoA.c demoB.c
PROGNAME = runA runB

# In Application.mk, we will automatically define variables
# prefixed with 'PROGKEY_' or 'ELFPROGKEY_'
# which used depends on builtin or elf

PROGKEY_home.apps.examples.myapp.demoA.o := runA
PROGKEY_apps.examples.myapp.demoB.o := runB

ELFPROGKEY_/home/apps/bin/runA :=  apps.examples.myapp.demoA.o
ELFPROGKEY_/home/apps/bin/runB :=  apps.examples.myapp.demoB.o

Use the mapped variable and cooperate with the target $@, so that the mismatch situation can be solved.

Impact

compilation and incremental compilation of all applications (include ELF mode)

Testing

CI build

[vikewang]

very good!