backslashes in variable definition

[Volker Boerchers]

Hi,

the _SOURCES values of our Makefile.am's are split into multiple lines
to improve readability like this

  libfoo_la_SOURCES = \
        foo.c \
        bar.c

However if one forgets a backslash the source files after that are
silently ignored by automake.

  libfoo_la_SOURCES = \
        foo.c                  # missing '\' 
        bar.c

These errors are hard to detect, at least for libraries since missing
dependencies are detected later.

The output of the attached example is (using automake 1.5 or 1.7.6):

  $ ./autogen.sh
  automake: configure.in: installing `./install-sh'
  automake: configure.in: installing `./mkinstalldirs'
  automake: configure.in: installing `./missing'
  automake: Makefile.am: installing `./COPYING'
  automake: configure.in: installing `./depcomp'

  $ ./configure
  [omitted]

  $ make
  make  all-am
  make[1]: Entering directory `/home/vboerchers/hello'
  source='hello.c' object='hello.o' libtool=no \
  depfile='.deps/hello.Po' tmpdepfile='.deps/hello.TPo' \
  depmode=gcc /bin/sh ./depcomp \
  gcc -DHAVE_CONFIG_H -I. -I. -I.     -g -O2 -c `test -f hello.c || echo 
'./'`hello.c
  gcc  -g -O2   -o hello  hello.o  
  hello.o: In function `main':
  /home/vboerchers/hello/hello.c:2: undefined reference to `f'
  collect2: ld returned 1 exit status
  make[1]: *** [hello] Error 1
  make[1]: Leaving directory `/home/vboerchers/hello'
  make: *** [all] Error 2

  $ make clean
  test -z "hello" || rm -f hello
  rm -f ChangeLog AUTHORS INSTALL Makefile.in Makefile NEWS README
  rm -f aclocal.m4 config.h* depcomp install-sh missing mkinstalldirs
  rm -f stamp* COPYING configure config.*
  bar.c
  make: execvp: bar.c: Permission denied
  make: *** [clean-local] Error 127

Please note that the 'bar.c' is attached to the 'clean-local'-target
that is placed *before* the erroneous variable definition.

Would it be possible for automake to detect such errors, and to give a
warning like in case of trailing backslashes at the end of a variable
definition?

Volker
-- 
Volker Börchers
TECON Systems AG

hello.tgz
Description: GNU Unix tar archive