New test; derived from glibc regression

From-SVN: r25507

gcc/testsuite/gcc.dg/990228-1.c

+/* Regression test for cpp.  The following input may cause core dumps
+   or # line markers in the middle of the line.  */
+/* { dg-do preprocess } */
+
+#define foo(string, arg) bar(2, string, arg)
+
+foo ("\
+\
+\
+\
+\
+\
+\
+\
+\
+\
+\
+",
+NULL);
+
+/*
+   { dg-final { if ![file exists 990228-1.i] { return }			} }
+   { dg-final { set tmp [grep 990228-1.i ".#"]				} }
+   { dg-final { if { [string length $tmp] == 0 } \{			} }
+   { dg-final {     pass "990228-1.c: linemarkers in middle of line"	} }
+   { dg-final { \} else \{						} }
+   { dg-final {     fail "990228-1.c: linemarkers in middle of line"    } }
+   { dg-final { \}							} }
+ */