Brain**** bracket matching could be better

[int-y1]

The current bracket matching code only counts the number of [ and ]. An invalid BF submission can pass this check, but it will receive a weird compile error message.

For example, this BF submission: ++++++]-----[++++
will receive this compile error:

tletestc.c:23:36: error: expected identifier or ‘(’ before ‘--’ token
     ++*p;++*p;++*p;++*p;++*p;++*p;}--*p;--*p;--*p;--*p;--*p;while(*p){++*p;++*p;++*p;++*p;
                                    ^~
tletestc.c:23:41: error: expected identifier or ‘(’ before ‘--’ token
     ++*p;++*p;++*p;++*p;++*p;++*p;}--*p;--*p;--*p;--*p;--*p;while(*p){++*p;++*p;++*p;++*p;
                                         ^~
tletestc.c:23:46: error: expected identifier or ‘(’ before ‘--’ token
     ++*p;++*p;++*p;++*p;++*p;++*p;}--*p;--*p;--*p;--*p;--*p;while(*p){++*p;++*p;++*p;++*p;
                                              ^~
tletestc.c:23:51: error: expected identifier or ‘(’ before ‘--’ token
     ++*p;++*p;++*p;++*p;++*p;++*p;}--*p;--*p;--*p;--*p;--*p;while(*p){++*p;++*p;++*p;++*p;
                                                   ^~
tletestc.c:23:56: error: expected identifier or ‘(’ before ‘--’ token
     ++*p;++*p;++*p;++*p;++*p;++*p;}--*p;--*p;--*p;--*p;--*p;while(*p){++*p;++*p;++*p;++*p;
                                                        ^~
tletestc.c:23:61: error: expected identifier or ‘(’ before ‘while’
     ++*p;++*p;++*p;++*p;++*p;++*p;}--*p;--*p;--*p;--*p;--*p;while(*p){++*p;++*p;++*p;++*p;
                                                             ^~~~~

The expected error message is: Unmatched brackets