* configure.in: Call AC_FUNC_ALLOCA, to see if we have alloca.

* eval.c: Add necessary CPP cruft to support that.
* configure, Makefile.in, scmconfig.h.in: regenerated.

libguile/scmconfig.h.in

@@ -7,9 +7,16 @@
 #undef _ALL_SOURCE
 #endif
 
+/* Define if using alloca.c.  */
+#undef C_ALLOCA
+
 /* Define to empty if the keyword does not work.  */
 #undef const
 
+/* Define to one of _getb67, GETB67, getb67 for Cray-2 and Cray-YMP systems.
+   This function is required for alloca.c support on those systems.  */
+#undef CRAY_STACKSEG_END
+
 /* Define to the type of elements in the array set by `getgroups'.
    Usually this is either `int' or `gid_t'.  */
 #undef GETGROUPS_T
@@ -17,6 +24,12 @@
 /* Define to `int' if <sys/types.h> doesn't define.  */
 #undef gid_t
 
+/* Define if you have alloca, as a function or macro.  */
+#undef HAVE_ALLOCA
+
+/* Define if you have <alloca.h> and it should be used (not on Ultrix).  */
+#undef HAVE_ALLOCA_H
+
 /* Define if your struct stat has st_blksize.  */
 #undef HAVE_ST_BLKSIZE
 
@@ -45,6 +58,15 @@
 /* Define as the return type of signal handlers (int or void).  */
 #undef RETSIGTYPE
 
+/* If using the C implementation of alloca, define if you know the
+   direction of stack growth for your system; otherwise it will be
+   automatically deduced at run-time.
+ STACK_DIRECTION > 0 => grows toward higher addresses
+ STACK_DIRECTION < 0 => grows toward lower addresses
+ STACK_DIRECTION = 0 => direction of growth unknown
+ */
+#undef STACK_DIRECTION
+
 /* Define if you have the ANSI C header files.  */
 #undef STDC_HEADERS