AC_*_IFELSE and paths with spaces

[Vladimir Panov]

Hi.

Suppose that I have an include directory that has a space in its path. I 
add it to $CPPFLAGS with quotes, e.g.:
CPPFLAGS="-I\"/path with a space\""
If I try AC_COMPILE_IFELSE (or AC_LINK_IFELSE), the compiler sees the 
include directory this way (literally, i.e. including the quotes):
"/path with a space"
On the other hand, this approach (adding -I"/path with a space" to 
$CPPFLAGS) works for all the make versions I have tried. I suspect the 
difference is that configure doesn't spawn a new copy of the shell to 
execute the compiler, while make does.

My question is - how do I add paths with spaces to $CPPFLAGS, $LDFLAGS, 
etc so that the AC_*_IFELSE macros would pass them correctly to the 
compiler?

Vlado