Temp fix GCC alloca for cron, etc

libc/include/alloca.h

@@ -1,15 +1,27 @@
 #ifndef __ALLOCA_H
 #define __ALLOCA_H
+/*
+ * Stack-checking alloca for GCC and OWC
+ */
 
 // void *alloca(size_t);
 
-int __stackavail(unsigned int size);
-#define __ALLOCA_ALIGN(s)   (((s)+(sizeof(int)-1))&~(sizeof(int)-1))
-
 #define alloca(s)           (__stackavail(__ALLOCA_ALIGN(s))?   \
                                  __alloca(__ALLOCA_ALIGN(s)): (void *)0)
 
+#define __ALLOCA_ALIGN(s)   (((s)+(sizeof(int)-1))&~(sizeof(int)-1))
+
+#ifdef __GNUC__
+/* The compiler auto-aligns the stack from the parameter somewhat strangely:
+ * 0 -> 0, 1 -> 2, 2 -> 4, 3 -> 4, 4 -> 6 etc.
+ * Thus, __stackavail should check for two more bytes available than asked for.
+ */
+#define __alloca(s)         __builtin_alloca(s)
+#define __stackavail(s)     0           /* temp no stack checking */
+#endif
+
 #ifdef __WATCOMC__
+int __stackavail(unsigned int size);
 #pragma aux __stackavail "*" __modify __nomemory
 
 extern void __based(__segname("_STACK")) *__alloca(unsigned int __size);