am__append drops line continuation chars

[Ralf Corsepius]

Hi,

If using a Makefile.am which triggers automake to using am_append, line
continuation char get lost:

Example Makefile.am:

include_foo_HEADERS =  0.h
if A
include_foo_HEADERS += a0.h \
  a1.h
endif
if B
include_foo_HEADERS += b0.h \
  b1.h
endif


Automake-1.7.1 and automake-1.7.1b generated Makefile.ins contain this:

@address@hidden = a0.h
@A_TRUE@  a1.h
                                                                       
@address@hidden = b0.h
@B_TRUE@  b1.h

Note, the '\' from the include_foo_HEADERS += 
have got lost, silently causing the resulting Makefile.in to be broken.

Ralf