Fix problem using alloca function, executable crashed even with a exception handler function, when try to allocate INT_MAX. Patch provided by Jason Hood in private e-mail, when I ask to him for help. He say: Feel free to pass it on to the mailing list.

lib/alloca86-bt.S

@@ -14,10 +14,10 @@ __bound_alloca:
 #ifdef TCC_TARGET_PE
 p4:
     cmp     $4096,%eax
-    jle     p5
+    jb      p5
+    test    %eax,-4096(%esp)
     sub     $4096,%esp
     sub     $4096,%eax
-    test    %eax,(%esp)
     jmp p4
 
 p5:

lib/alloca86.S

@@ -13,10 +13,10 @@ alloca:
 #ifdef TCC_TARGET_PE
 p1:
     cmp     $4096,%eax
-    jle     p2
+    jb      p2
+    test    %eax,-4096(%esp)
     sub     $4096,%esp
     sub     $4096,%eax
-    test    %eax,(%esp)
     jmp p1
 p2:
 #endif

lib/alloca86_64.S

@@ -17,10 +17,10 @@ alloca:
 #ifdef TCC_TARGET_PE
 p1:
     cmp     $4096,%rax
-    jle     p2
+    jb      p2
+    test    %rax,-4096(%rsp)
     sub     $4096,%rsp
     sub     $4096,%rax
-    test    %rax,(%rsp)
     jmp p1
 p2:
 #endif