Use libc assert(); fix dependencies; unbreak isduo().

Switch from custom assert() to libc assert() in mach/proto/as.
Continue to disable asserts if DEBUG == 0.

This change found a problem in the build system; comm2.y was missing
depedencies on comm0.h and comm1.h.  Add the missing dependencies to
the cppfile rule.  Allow the dependencies by modifying cppfile in
first/build.lua to act like cfile if t.dir is false.

Now that comm2.y gets rebuilt, I must fix the wrong prototype of
yyparse() in comm1.h.

I got unlucky as induo() in comm5.c was reading beyond the end of the
array.  It found an operator "= " ('=' then space) in the garbage, so
it returned a garbage token number, and "VAR = 123" became a syntax
error.  Unbreak induo() by terminating the array.

first/build.lua

@@ -92,7 +92,9 @@ definerule("cppfile",
 
 		local hdrpaths = {}
 		for _, t in pairs(e.deps) do
-			hdrpaths[#hdrpaths+1] = "-I"..t.dir
+			if t.dir then
+				hdrpaths[#hdrpaths+1] = "-I"..t.dir
+			end
 		end
 		hdrpaths = uniquify(hdrpaths)
 

mach/proto/as/build.lua

@@ -21,6 +21,8 @@ definerule("build_as",
 			srcs = { "mach/proto/as/comm2.y" },
 			outleaf = "comm2.y",
 			deps = {
+				"mach/proto/as/comm0.h",
+				"mach/proto/as/comm1.h",
 				"h+emheaders",
 				archlib,
 			},

mach/proto/as/comm0.h

@@ -105,16 +105,16 @@ _include	"out.h"
 #include	"out.h"
 #endif
 
-#if DEBUG == 0
+/*
-#define	assert(ex)	/* nothing */
+ * Define assert().  Disable assertions if DEBUG == 0.
+ */
+#if DEBUG == 0 && !defined(NDEBUG)
+#define NDEBUG
 #endif
-
+#ifdef _include
-#if DEBUG == 1
+_include <assert.h>
-#define	assert(ex)	{if (!(ex)) assert1();}
+#else
-#endif
+#include <assert.h>
-
-#if DEBUG == 2
-#define	assert(ex)	{if (!(ex)) assert2(__FILE__, __LINE__);}
 #endif
 
 #define	CTRL(x) 	((x) & 037)

mach/proto/as/comm1.h

@@ -105,7 +105,7 @@ extern int	curr_token;
 
 /* forward function declarations */
 /* comm2.y */
-void	 yyparse(void);
+int	 yyparse(void);
 /* comm4.c */
 void	 stop(void);
 void	 newmodule(const char *);

mach/proto/as/comm5.c

@@ -283,6 +283,7 @@ induo(int c)
 		('>'<<8) | '>', OP_RR,
 		('|'<<8) | '|', OP_OO,
 		('&'<<8) | '&', OP_AA,
+		0  /* terminates array */
 	};
 	short *p;
 

mach/proto/as/comm6.c

@@ -79,10 +79,8 @@ newident(item_t *ip, int typ)
 void
 newlabel(item_t *ip)
 {
-#if DEBUG != 0
+#if defined(THREE_PASS) && !defined(NDEBUG)
-#ifdef THREE_PASS
 	ADDR_T oldval = ip->i_valu;
-#endif
 #endif
 
 	if (DOTSCT == NULL)

mach/proto/as/comm7.c

@@ -406,22 +406,6 @@ void fatal(const char* s, ...)
 	va_end(ap);
 }
 
-#if DEBUG == 2
-assert2(file, line)
-char *file;
-{
-	fatal("assertion failed (%s, %d)", file, line);
-}
-#endif
-
-#if DEBUG == 1
-assert1()
-{
-	fatal("assertion failed");
-	abort();
-}
-#endif
-
 /* VARARGS1 */
 void serror(const char* s, ...)
 {