unconditionally, use macros with arguments.
* include/_slang.h: Make it clear which parts are disabled
for compatibility with glib.
* include/slinclud.h: Include malloc.h only if STDC_HEADERS is
not defined.
directory to avoid the need to rename slang.h.
* Makefile.am: Adjust file list. Add "-Iinclude" to the
compiler flags.
* include/jdmacros.h: Rewrite to use glib.
* slmisc.c: Trim to include only needed functions.