Add test for five escapes before n

test cases/common/42 string operations/meson.build

@@ -83,6 +83,8 @@ bs_n = '''\n'''
 bs_nl = '''\
 '''
 bs_bs_n = '''\\n'''
+bs_bs_nl = '''\\
+'''
 
 assert('\b' == bs_b, 'Single backslash broken')
 assert('\\b' == bs_b, 'Double backslash broken')
@@ -92,3 +94,4 @@ assert('\n' == nl, 'Newline escape broken')
 assert('\\n' == bs_n, 'Double backslash broken before n')
 assert('\\\n' == bs_nl, 'Three backslash broken before n')
 assert('\\\\n' == bs_bs_n, 'Four backslash broken before n')
+assert('\\\\\n' == bs_bs_nl, 'Five backslash broken before n')