C front-end: support preprocessor line markers in inline asm

The lexer previously did not consider the case of preprocessor line
markers occurring in between keywords belonging to an inline assembly
block.

Author: tautschnig

regression/ansi-c/asm2/main.c

@@ -6,7 +6,13 @@ int main()
 #ifdef __GNUC__
   asm goto ("jc %l[error];"
       : : "r"(x), "r"(&y) : "memory" : error);
-  asm __inline volatile("jc %l[error];" : : "r"(x), "r"(&y) : "memory" : error);
+  asm
+#   11
+    __inline volatile("jc %l[error];"
+                      :
+                      : "r"(x), "r"(&y)
+                      : "memory"
+                      : error);
 #endif
 error:
   return 0;

src/ansi-c/scanner.l

@@ -1637,6 +1637,10 @@ __decltype          { if(PARSER.cpp98 &&
   /* The following ugly stuff avoids two-token lookahead in the parser;
      e.g., asm void f()  vs.  asm ("xyz") or asm { ... } */
 <GCC_ASM>{
+{cpplineno}     {
+                  preprocessor_line(yytext, PARSER);
+                  PARSER.set_line_no(PARSER.get_line_no()-1);
+                }
 {ws}            { /* ignore */ }
 {newline}       { /* ignore */ }
 "{"             { yyless(0); BEGIN(GRAMMAR); loc(); PARSER.asm_block_following=true; return TOK_GCC_ASM_PAREN; }