kbuild: fix ld-option function

The kbuild's ld-option function is broken because
the command
  $(CC) /dev/null -c -o "$$TMPO"
does not create object file!

I have used a relatively old mips gcc 3.4.6 cross-compiler
and a relatively new gcc 4.7.2 to check this fact
but the results are the same.

EXAMPLE:
  $ rm /tmp/1.o
  $ mips-linux-gcc /dev/null -c -o /tmp/1.o
  mips-linux-gcc: /dev/null: linker input file unused because linking not done
  $ ls -la /tmp/1.o
  ls: cannot access /tmp/1.o: No such file or directory

We can easily fix the problem by adding
the '-x c' compiler option.

EXAMPLE:
  $ rm /tmp/1.o
  $ mips-linux-gcc -x c /dev/null -c -o /tmp/1.o
  $ ls -la /tmp/1.o
  -rw-r--r-- 1 antony antony 778 Apr  2 20:40 /tmp/1.o

Also fix wrong ld-option example.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
This commit is contained in:
Antony Pavlov 2013-04-03 18:42:33 +04:00 committed by Michal Marek
parent a937536b86
commit 5b83df2b46
2 changed files with 2 additions and 2 deletions

View file

@ -593,7 +593,7 @@ more details, with real examples.
Example:
#Makefile
LDFLAGS_vmlinux += $(call really-ld-option, -X)
LDFLAGS_vmlinux += $(call ld-option, -X)
=== 4 Host Program support

View file

@ -148,7 +148,7 @@ cc-ldoption = $(call try-run,\
# ld-option
# Usage: LDFLAGS += $(call ld-option, -X)
ld-option = $(call try-run,\
$(CC) /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
$(CC) -x c /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
# ar-option
# Usage: KBUILD_ARFLAGS := $(call ar-option,D)