Fixes:

    #define S "//foo"
    #define S "/*foo"

bug where comments are interpreted inside strings.

The fix assumes strings and char literals are essentially
the same.  Screwups will be caught by the compiler on
macro expansion.  This decision was made to simplify
the implementation and to avoid duplication of code.

Notes:
Thu Feb 10 18:11:36 EST 2005 rsc
    This fix breaks the following program:
    
    #include <u.h>
    #include <libc.h>
    
    #define x(y) "y\n"
    
    void
    main(void)
    {
    	print(x(hello world));
    }
    
    Replacing within quotes is occasionally useful
    for "stringizing", especially since Ken doesn't
    support the ANSI preprocessor # foo syntax.
    
    I think the comment problem is still fixable
    without breaking the above program, just not
    this way.
    


Reference: /n/sources/patch/sorry/macbody
Date: Thu Feb 10 21:10:49 CET 2005
Reviewed-by: rsc

--- /sys/src/cmd/cc/macbody	Thu Feb 10 21:06:58 2005
+++ /sys/src/cmd/cc/macbody	Thu Feb 10 21:06:57 2005
@@ -234,6 +234,34 @@
 			base[len++] = 'a' + i;
 			continue;
 		}
+		if (c == '\'' || c == '"') {
+			int e;
+
+			base = allocn(base, len, 1);
+			base[len++] = c;
+			e = c;
+
+			for (;;) {
+				int p;
+
+				p = c;
+				if ((c = getc()) == '\n')
+					break;
+
+				base = allocn(base, len, 1);
+				base[len++] = c;
+
+				if (p == '\\' && c == e)
+					continue;
+
+				if (c == e) {
+					c = getc();
+					break;
+				}
+			}
+
+			continue;
+		}
 		if(c == '/') {
 			c = getc();
 			if(c == '/'){