* m4/debug.m4, m4/devel.m4, m4/gccoptim.m4, m4/ndebug.m4: New files.

* Makefile.am (EXTRA_DIST): Add them.
* configure.ac: Call adl_ENABLE_DEVEL, adl_ENABLE_DEBUG, ad_GCC_OPTIM,
and adl_NDEBUG.

m4/gccoptim.m4

@@ -0,0 +1,33 @@
+dnl  Adapted from Akim Demaille <akim@epita.fr> ad_GCC_WARNINGS.
+AC_DEFUN([ad_GCC_OPTIM],
+[AC_ARG_ENABLE([optimizations],
+ [AC_HELP_STRING([--disable-optimizations],
+  [turn off aggressive optimizations])])
+ if test -n "$GCC" -a "${enable_optimizations-yes}" = "yes"; then
+  AC_CACHE_CHECK([for gcc optimization options], ac_cv_prog_gcc_opt_flags,
+  [changequote(,)dnl
+  cat > conftest.$ac_ext <<EOF
+#line __oline__ "configure"
+int main(int argc, char *argv[]) { return argv[argc-1] == 0; }
+EOF
+  changequote([,])dnl
+  cf_save_CFLAGS="$CFLAGS"
+  ac_cv_prog_gcc_opt_flags="-O3"
+  for cf_opt in \
+    ffast-math \
+    fstrict-aliasing \
+    fomit-frame-pointer
+  do
+    CFLAGS="$cf_save_CFLAGS $ac_cv_prog_gcc_opt_flags -$cf_opt"
+    if AC_TRY_EVAL([ac_compile]); then
+      ac_cv_prog_gcc_opt_flags="$ac_cv_prog_gcc_opt_flags -$cf_opt"
+    fi
+  done
+  rm -f conftest*
+  CFLAGS="$cf_save_CFLAGS $ac_cv_prog_gcc_opt_flags"])
+else
+  case $enable_optimizations in
+    no) ;;
+    *) CFLAGS="$CFLAGS $enable_optimizations" ;;
+  esac
+fi])